Laryngeal theory

The laryngeal theory is a generally accepted theory of historical linguistics which proposes the existence of a set of three (or more) consonant sounds that appear in most current reconstructions of the Proto-Indo-European language (PIE). These sounds have since disappeared in all existing Indo-European languages, but some laryngeals are believed to have existed in the Anatolian languages, including Hittite.

The evidence for them is mostly indirect, but serves as an explanation for differences between vowel sounds across Indo-European languages. For example, Sanskrit and Ancient Greek, two descendents of PIE, exhibit many similar words that have differing vowel sounds. Assume that the Greek word contains the vowel [e] and the corresponding Sanskrit word contains [i] instead. The laryngeal theory postulates these words originally had the same vowels, but a neighboring consonant which had since disappeared had altered the vowels. If one labeled the hypothesized consonant as [h₁], then the original PIE word may have contained something like [eh₁] or [ih₁], or perhaps a completely different sound such as [ah₁].

The original phonetic values of the laryngeal sounds remain controversial (See below).

Discovery

The beginnings of the theory were proposed by Ferdinand de Saussure in 1879, in an article chiefly devoted to something else altogether (demonstrating that *a and *o were separate phonemes in PIE). Saussure's observations, however, did not achieve any general currency until after Hittite was discovered and deciphered in the early 20th century. Hittite had a sound or sounds written with symbols from the Akkadian syllabary conventionally transcribed as ḫ, as in te-iḫ-ḫi "I put, am putting". Various more or less obviously unsatisfactory proposals were made to connect these (or this) to the PIE consonant system as then reconstructed. It remained for Jerzy Kuryłowicz (Études indoeuropéennes I, 1935) to propose that these sounds lined up with Saussure's conjectures. Since then, the laryngeal theory (in one or another form) has been accepted by most Indo-Europeanists.

The late discovery of these sounds by Indo-Europeanists is largely due to the fact that Hittite and the other Anatolian languages are the only Indo-European languages where at least some of them are attested directly and consistently as consonantal sounds. Otherwise, their presence is to be seen mostly through the effects they have on neighboring sounds, and on patterns of alternation that they participate in; when a laryngeal is attested directly, it is usually as a vowel (as in the Greek examples below). Most Indo-Europeanists accept at least some version of laryngeal theory because their existence simplifies some otherwise hard-to-explain sound changes and patterns of alternation that appear in the Indo-European languages, and solves some minor mysteries, such as why verb roots containing only a consonant and a vowel have only long vowels e.g. *dō- "give"; re-reconstructing *deh₃- instead not only accounts for the patterns of alternation more economically than before, but brings the root into line with the basic consonant - vowel - consonant Indo-European type.

There are many variations of the Laryngeal theory. Some scholars, such as Oswald Szemerényi, reconstruct just one. Some follow Jaan Puhvel's reconstruction of eight or more (in his contribution to Evidence for Laryngeals, ed. Werner Winter). Most scholars work with a basic three:

*h₁, the "neutral" laryngeal
*h₂, the "a-colouring" laryngeal
*h₃, the "o-colouring" laryngeal

Many scholars, however, either insist on or allow for a fourth consonant, *h₄, which differs from *h₂ only in not being reflected as Anatolian ḫ. Accordingly, except when discussing Hittite evidence, the theoretical existence of an *h₄ contributes little. Another such theory, but much less generally accepted, is Winfred P. Lehmann's view, on the basis of inconsistent reflexes in Hittite, that *h₁ was actually two separate sounds. (He assumed that one was a glottal stop and the other a glottal fricative.)

Some direct evidence for laryngeal consonants from Anatolian:

PIE *a is a rarish sound, and in an uncommonly large number of good etymologies it is word-initial. Thus PIE (traditional) *anti "in front of and facing" > Greek antí "against"; Latin ante "in front of, before"; (Sanskrit ánti "near; in the presence of"). But in Hittite there is a noun ḫants "front, face", with various derivatives (ḫantezzi "first", and so on), pointing to a PIE root-noun *h₂ent- "face" (of which *h₂enti would be the locative singular). (It does not necessarily follow that all reconstructed forms with initial *a should automatically be rewritten *h₂e.)

Similarly, the traditional PIE reconstruction for 'sheep' is *owi- (a y-stem, not an i-stem) whence Sanskrit अवि-, Latin ovis, Greek ὄϊς. But now Luwian has 𒄩𒀀𒌑𒄿𒅖-, indicating instead a reconstruction *h₃ewi-.

But if laryngeals as consonants were first spotted in Hittite only in 1935, what was the basis for Saussure's conjectures some 55 years earlier?

They sprang from a reanalysis of how the patterns of vowel alternation in Proto-Indo-European roots of different structure aligned with one another.

A feature of Proto-Indo-European morpheme structure was a system of vowel alternations christened ablaut ("alternate sound") by early German scholars and still generally known by that term (except in French, where the term apophonie is preferred). Several different such patterns have been discerned, but the commonest one, by a wide margin, is e/o/zero alternation found in a majority of roots, in many verb and noun stems, and even in some affixes (the genitive singular ending, for example, is attested as *-es, *-os, and *-s). The different states are called ablaut grades; e-grade and o-grade are together "full grades", and the total absence of any vowel is "zero grade".

Thus the root *sed- "to sit (down)" (roots are traditionally cited in the e-grade, if they have one) has three different shapes: *sed-, *sod-, and *sd-. This kind of patterning is found throughout the PIE root inventory and is transparent:

*sed-: in Latin sedeo "am sitting", Old English sittan "to sit" < *set-ja- (with umlaut) < *sed-; Greek hédrā "seat, chair" < *sed-.

*sod-: in Latin solium "throne" (Latin l sporadically replaces d between vowels, said by Roman grammarians to be a Sabine trait) = Old Irish suideⁿ /suð'e/ "a sitting" (all details regular from PIE *sod-yo-m); Gothic satjan = Old English settan "to set" (causative) < *sat-ja- (umlaut again) < PIE *sod-eye-. PIE *se-sod-e "sat" (perfect) > Sanskrit sa-sād-a per Brugmann's law.

*sd-: in compounds, as *ni- "down" + *sd- = *nisdos "nest": English nest < Proto-Germanic *nistaz, Latin nidus#Latin < *nizdos (all regular developments). The 3pl (third person plural) of the perfect would have been *se-sd-ṛ whence Indo-Iranian *sazdṛ, which gives (by regular developments) Sanskrit sedur /sēdur/.

Now, in addition to the commonplace roots of consonant + vowel + consonant structure there are also well-attested roots like *dhē- "put, place": these end in a vowel, which is always long in the categories where roots like *sed- have full grades; and in those forms where zero grade would be expected, before an affix beginning with a consonant, we find a short vowel, reconstructed as *ə, or schwa (more formally, schwa primum indogermanicum). The cross-language correspondences of this vowel are different from the other five short vowels. (Before an affix beginning with a vowel, there is no trace of a vowel in the root, as shown below.)

Whatever caused a short vowel to disappear entirely in roots like *sed-/*sod-/*sd-, it was a reasonable inference that a long vowel under the same conditions would not quite disappear, but would leave a sort of residue. This residue is reflected as i in Indic while dropping in Iranian; it gives variously e, a, o in Greek; it mostly falls together with the reflexes of PIE *a in the other languages (always bearing in mind that short vowels in non-initial syllables undergo various adventures in Italic, Celtic, and Germanic):

*dō- "give": in Latin donum "gift" = Old Irish dán /dāṅ/ and Sanskrit dâna- (â = ā with tonic accent); Greek δίδωμι (reduplicated present) "I give" = Sanskrit ददाति. But in the participles, Greek dotós "given" = Sanskrit ditá-, Latin datus all < *də-tó-.

*stā- "stand": in Greek ἵστημι (reduplicated present, regular from *si-stā-), Sanskrit a-sthā-t aorist "stood", Latin testāmentum "testimony" < *ter-stā- < *tri-stā- ("third party" or the like). But Sanskrit sthitá-"stood", Greek stasís "a standing", Latin supine infinitive statum "to stand".

Conventional wisdom lined up roots of the *sed- and *dō- types as follows:

Full Grades	Weak Grades
sed-, sod-	sd-	"sit"
dō-	də-, d-	"give"

But there are other patterns of "normal" roots, such as those ending with one of the six resonants (*y w r l m n), a class of sounds whose peculiarity in Proto-Indo-Eruopean is that they are both syllabic (vowels, in effect) and consonants, depending on what sounds are adjacent:

Root *bher-/bhor-/bhṛ- ~ bhr- "carry"

*bher-: in Latin fero#Latin = Greek φέρω, Avestan barā, Sanskrit भरति, Old Irish biur, Old Norse bera#Old Norse, Old English beran all "I carry"; Latin ferculum "bier, litter" < *bher-tlo- "implement for carrying".
*bhor-: in Gothic and Scandinavian barn "child" (= English dial. bairn), Greek phoréō "I wear [clothes]" (frequentative formation, *"carry around"); Sanskrit bhâra- "burden" (*bhor-o- via Brugmann's law).
*bhṛ- before consonants: Sanskrit bhṛ-tí- "a carrying"; Gothic gabaurþs /gaborθs/, Old English gebyrd /jebyrd/, Old High German geburt all "birth" < *gaburdi- < *bhṛ-tí-
*bhr- before vowels: Ved bibhrati 3pl. "they carry" < *bhi-bhr-ṇti; Greek di-phrós "chariot footboard big enough for two men" < *dwi-bhr-o-.

Saussure's insight was to align the long-vowel roots like *dō-, *stā- with roots like *bher-, rather than with roots of the *sed- sort. That is, treating "schwa" not as a residue of a long vowel but, like the *r of *bher-/*bhor-/*bhṛ-, an element that was present in the root in all grades, but which in full grade forms coalesced with an ordinary e/o root vowel to make a long vowel, with "coloring" (changed phonetics) of the e-grade into the bargain; the mystery element was seen by itself only in zero grade forms:

Full Grades	Zero Grade
bher-, bhor-	bhṛ- / bhr-	"carry"
deX, doX-	dẊ- / dX-	"give"

(Ẋ = syllabic form of the mystery element)

Saussure treated only two of these elements, corresponding to our *h₂ and *h₃. Later it was noticed that the explanatory power of the theory, as well as its elegance, were enhanced if a third element were added, our *h₁, which has the same lengthening and syllabifying properties as the other two but has no effect on the color of adjacent vowels. Saussure offered no suggestion as to the phonetics of these elements; his term for them, "coéfficients sonantiques", was not however a fudge, but merely the term in general use for glides, nasals, and liquids (i.e., the PIE resonants) as in roots like *bher-.

As mentioned above, in forms like *dwi-bhr-o- (etymon of Greek diphrós, above), the new "coéfficients sonantiques" (unlike the six resonants) have no reflexes at all in any daughter language. Thus the compound *mṇs-dheH- "to 'fix thought', be devout, become rapt" forms a noun *mṇs-dhH-o- seen in Proto-Indo-Iranian *mazdha- whence Sanskrit medhá- /mēdha/ "sacrificial rite, holiness" (regular development as in sedur < *sazdur, above), Avestan mazda- "name (originally an epithet) of the greatest deity".

There is another kind of unproblematic root, in which obstruents flank a resonant. In the zero grade, unlike the case with roots of the *bher- type, the resonant is therefore always syllabic (being always between two consonants). An example would be *bhendh- "tie, bind":

*bhendh-: in Germanic forms like Old English bindan "to tie, bind", Gothic bindan; Lithuanian beñdras "chum", Greek peĩsma "rope, cable" /pēsma/ < *phenth-sma < *bhendh-smṇ.
*bhondh-: in Sanskrit bandhá- "bond, fastening" (*bhondh-o-; Grassmann's law) = Old Icelandic bant, OE bænd; Old English bænd, Gothic band "he tied" < *(bhe)bhondh-e.
*bhṇdh-: in Sanskrit baddhá- < *bhṇdh-tó- (Bartholomae's law), Old English gebunden, Gothic bundan; German Bund "league". (English bind and bound show the effects of secondary (Middle English) vowel lengthening; the original length is preserved in bundle.)

This is all straightforward and such roots fit directly into the overall patterns. Less so are certain roots that seem sometimes to go like the *bher- type, and sometimes to be unlike anything else, with (for example) long syllabics in the zero grades while at times pointing to a two-vowel root structure. These roots are variously called "heavy bases", "dis(s)yllabic roots", and "seṭ roots" (the last being a term from Pāṇini's grammar. It will be explained below).

For example, the root "be born, arise" is given in the usual etymological dictionaries as follows:

(A) *ǵen-, *ǵon-, *ǵṇn-
(B) *ǵenə-, *ǵonə-, *ǵṆ- (where Ṇ = a long syllabic n)

The (A) forms occur when the root is followed by an affix beginning with a vowel; the (B) forms when the affix begins with a consonant. As mentioned, the full-grade (A) forms look just like the *bher- type, but the zero grades always and only have reflexes of syllabic resonants, just like the *bhendh- type; and unlike any other type, there is a second root vowel (always and only *ə) following the second consonant:

*ǵen(ə)-

(A) PIE *ǵenos- neut s-stem "race, clan" > Greek (Homeric) génos, -eos, Sanskrit jánas-, Avestan zanō, Latin genus, -eris.
(B) Greek gené-tēs "begetter, father"; géne-sis < *ǵenə-ti- "origin"; Sanskrit jáni-man- "birth, lineage", jáni-tar- "progenitor, father", Latin genitus "begotten" < genatos.

*ǵon(e)-

(A) Sanskrit janayati "beget" = Old English cennan /kennan/ < *ǵon-eye- (causative); Sanskrit jána- "race" (o-grade o-stem) = Greek gónos, -ou "offspring".
(B) Sanskrit jajāna 3sg. "was born" < *ǵe-ǵon-e.

*ǵṇn-/*ǵṆ-

(A) Gothic kuni "clan, family" = OE cynn /künn/, English kin; Rigvedic jajanúr 3pl.perfect < *ǵe-ǵṇn- (a relic; the regular Sanskrit form in paradigms like this is jajñur, a remodeling).
(B) Sanskrit jātá- "born" = Latin nātus (Old Latin gnātus, and cf. forms like cognātus "related by birth", Greek kasí-gnētos "brother"); Greek gnḗsios "belonging to the race". (The ē in these Greek forms can be shown to be original, not Attic-Ionic developments from Proto-Greek *ā.)

On the term "seṭ". The Pāṇinian term "seṭ" (that is, sa-i-ṭ) is literally "with an /i/". This refers to the fact that roots so designated, like jan- "be born", have an /i/ between the root and the suffix, as we've seen in Sanskrit jánitar-, jániman-, janitva (a gerund). Cf. such formations built to "aniṭ" ("without an /i/") roots, such as han- "slay": hántar- "slayer", hanman- "a slaying", hantva (gerund). In Pāṇini's analysis, this /i/ is a linking vowel, not properly a part of either the root or the suffix. It is simply that some roots are in effect in the list consisting of the roots that (as we would put it) "take an -i-".

But historians have the advantage here: the peculiarities of alternation, the "presence of /i/", and the fact that the only vowel allowed in second place in a root happens to be *ə, are all neatly explained once *ǵenə- and the like were understood to be properly *ǵenH-. That is, the patterns of alternation, from the point of view of Indo-European, were simply those of *bhendh-, with the additional detail that *H, unlike obstruents (stops and *s) would become a syllable between two consonants, hence the *ǵenə- shape in the Type (B) formations, above.

The startling reflexes of these roots in zero grade before a consonant (in this case, Sanskrti ā, Greek nē, Latin nā, Lithuanian ìn) is explained by the lengthening of the (originally perfectly ordinary) syllabic resonant before the lost laryngeal, while the same laryngeal protects the syllabic status of the preceding resonant even before an affix beginning with a vowel: the archaic Vedic form jajanur cited above is structurally quite the same (*ǵe-ǵṇh₁-ṛ) as a form like *da-dṛś-ur "they saw" < *de-dṛḱ-ṛ.

Incidentally, redesigning the root as *ǵenH- has another consequence. Several of the Sanskrit forms cited above come from what look like o-grade root vowels in open syllables, but fail to lengthen to -ā- per Brugmann's law. All becomes clear when it is understood that in such forms as *ǵonH- before a vowel, the *o is not in fact in an open syllable. And in turn that means that a form like jajāna "was born", which apparently does show the action of Brugmann's law, is actually a false witness: in the Sanskrit perfect tense, the whole class of seṭ roots, en masse, acquired the shape of the aniṭ 3sing. forms. (See Brugmann's law for further discussion.)

There are also roots ending in a stop followed by a laryngeal, as *pleth₂-/*pḷth₂- "spread, flatten", from which Sanskrit pṛthú- "broad" masc. (= Avestan pərəθu-), pṛthivī- fem., Greek platús (zero grade); Skt. prathimán- "wideness" (full grade), Greek platamṓn "flat stone". The laryngeal explains (a) the change of *t to *th in Proto-Indo-Iranian, (b) the correspondence between Greek -a-, Sanskrit -i- and no vowel in Avestan (Avestan pərəθwī "broad" fem. in two syllables vs Sanskrit pṛthivī- in three).

Caution has to be used in interpreting data from Indic in particular. Sanskrit remained in use as a poetic, scientific, and classical language for many centuries, and the multitude of inherited patterns of alternation of obscure motivation (such as the division into seṭ and aniṭ roots) provided models for coining new forms on the "wrong" patterns. There are many forms like tṛṣita- "thirsty" and tániman- "slenderness", that is, seṭ formations to unequivocally aniṭ roots; and conversely aniṭ forms like píparti "fills", pṛta- "filled", to securely seṭ roots (cf. the "real" past participle, pūrṇá-). Sanskrit preserves the effects of laryngeal phonology with wonderful clarity, but looks upon the historical linguist with a threatening eye: for even in Vedic Sanskrit, the evidence has to be weighed carefully with due concern for the antiquity of the forms and the overall texture of the data. (It is no help that Proto-Indo-European itself had roots which varied somewhat in their makeup, as *ǵhew- and *ǵhewd-, both "pour"; and some of these "root extensions" as they're called, for want of any more analytical term, are, unluckily, laryngeals.)

Stray laryngeals can be found in isolated or seemingly isolated forms; here the three-way Greek reflexes of syllabic *h₁, *h₂, *h₃ are particularly helpful, as seen below. (Comments on the forms follow.)

*ḥ₁ in Greek ánemos "wind" (cf. Latin animus "breath, spirit; mind", Vedic aniti "breathes") < *anə- "breathe; blow" (now *h₂enh₁-). Perhaps also Greek híeros "mighty, super-human; divine; holy", cf. Sanskrit iṣirá- "vigorous, energetic".

*ḥ₂ in Greek patḗr "father" = Sanskrit pitár-, Old English fæder, Gothic fadar, Latin pater. Also *meǵḥ₂ "big" neut. > Greek méga, Sanskrit máha.

*ḥ₃ in Greek árotron "plow" = Welsh aradr, Old Norse arðr, Lithuanian árklas.

Comments

The Greek forms ánemos and árotron are particularly valuable because the verb roots in question are extinct in Greek as verbs. This means that there is no possibility of some sort of analogical interference, as for example happened in the case of Latin arātrum "plow", whose shape has been distorted by the verb arāre "to plow" (the exact cognate to the Greek form would have been *aretrum). It used to be standard to explain the root vowels of Greek thetós, statós, dotós "put, stood, given" as analogical. Most scholars nowadays probably take them as original, but in the case of "wind" and "plow", the argument can't even come up.

Regarding Greek híeros, the pseudo-participle affix *-ro- is added directly to the verb root, so *isḥ₁-ro- > *isero- > *ihero- > híeros (with regular throwback of the aspiration to the beginning of the word), and Sanskrit iṣirá-. There seems to be no question of the existence of a root *eysH- "vigorously move/cause to move". If the thing began with a laryngeal, and most scholars would agree that it did, it would have to be *h₁-, specifically; and that's a problem. A root of the shape *h₁eysh₁- is not possible. Indo-European had no roots of the type *mem-, *tet-, *dhredh-, i.e., with two copies of the same consonant. But Greek attests an earlier (and rather more widely-attested) form of the same meaning, híaros. If we reconstruct *h₁eysh₂-, all of our problems are solved in one stroke. The explanation for the híeros/híaros business has long been discussed, without much result; laryngeal theory now provides the opportunity for an explanation which did not exist before, namely metathesis of the two laryngeals. It's still only a guess, but it's a much simpler and more elegant guess than the guesses available before.

The syllabic *ḥ₂ in *pḥ₂ter- "father" might not really be isolated. Certain evidence shows that the kinship affix seen in "mother, father" etc. might actually have been *-h₂ter- instead of *-ter-. The laryngeal syllabified after a consonant (thus Greek patḗr, Latin pater, Sanskrit pitár-; Greek thugátēr, Sanskrit duhitár- "daughter") but lengthened a preceding vowel (thus say Latin māter "mother", frāter "brother") — even when the "vowel" in question was a syllabic resonant, as in Sanskrit yātaras "husbands' wives" < *yṆt- < *yṇ-h₂ter-).

Evidence from Uralic

Further evidence of the laryngeals has been found in Uralic (Finno-Ugric) languages. While Proto-Uralic and PIE have not been proven to be genetically related, some words reconstructed into Uralic 'proto-dialects' (such as Proto-Finno-Ugric, Proto-Finno-Permic etc.) have been identified as likely borrowings from very early Indo-European dialects, such as Hungarian név, Finnish=Proto-Uralic (*)nimi and English name, Latin nōmen, Greek ónoma, etc.; Hungarian méz ’honey’, Finnish (nominative mesi) oblique stem = Proto-Finno-Ugric (*)mete- ’honey’, and English mead, Greek methu ’wine’, Sanskrit mádhu 'honey' etc.; and Finno-Ugric *porćas ‘piglet’ and PIE *porḱ- that gives Latin porcus 'hog', OE fearh (> Engl. farrow 'young pig'), Lithuanian par̃šas ’piglet, castrated boar’. There are several criteria to date such borrowings, the most reliable ones coming from historical phonology. For example the Finno-Mordvin form *porćas (Permic and Ugric forms may be separate borrowings) presupposes a source for the word predating the depalatalisation of centum languages or predating the later development into the Baltic *š, which is reflected as Finn. h in borrowings.

Work particularly associated with research of the scholar Jorma Koivulehto has identified a number of additions to the list of Finnic loanwords from an Indo-European source or sources whose particular interest is the apparent correlation of PIE laryngeals with three post-alveolar phonemes (or their later reflexes) in the Finnic forms. If so, this would point to a great antiquity for the borrowings, since no attested Indo-European language neighbouring Uralic has consonants as reflexes of laryngeals. And it would bolster the idea that laryngeals were distinctly consonantal, phonetically.

Three Uralic phonemes reflect PIE laryngeals. In post-vocalic positions both the post-alveolar fricatives that ever existed in Uralic are represented: firstly a possibly velar one, theoretically reconstructed much as the PIE laryngeals (conventionally marked *x), in the very oldest borrowings and secondly a grooved one (*š as in shoe becoming modern Finnic h) in some younger ones. The velar plosive k is the third reflex and the only one found word-initially (a possible older word-initial reflex *x would have disappeared in Uralic without a trace). In intervocalic position the reflex k is probably younger than either of the two former ones. The fact that Finnic may have plosive reflexes for PIE laryngeals is to be expected under well documented Finnic phonological behaviour and does not mean much for tracing the phonetic value of PIE laryngeals (cf. Finnish Kansa ‘people’<= Gmc *χansā ’company, troupe, party, crowd’ (cf. German Hansa), Finnish kärsiä ‘suffer, endure’<= Gmc *χarđia- ’endure’ (cf. E. hard), Finnish pyrkiä <= PGmc. *wurk(i)ja- ‘work, work for’ etc).

The correspondences work in a perfectly equal way for h₁, h₂ and h₃. Thus
1) PIE laryngeals correspond to PU fricative *x in wordstems like:
-Finnish nai-/naa- 'woman' < PU *näχi-/*naχi- <= PIE *[g^wnah₂-] = */g^wneh₂-/ > Sanskrit gnā́ 'goddess', OIr. mná (gen. of ben), ~Greek gunē ‘woman’(cognate to Engl. queen)
-Finnish tuo- 'bring' ~ Samoyed tāś 'give' < PU *toχi <= PIE *[doh₃-] = */deh₃-/ > Greek didōmi, Lat. dō-, Old Lith. dúomi 'give', Hittite dā 'take'
2) PIE laryngeals correspond to Pre-Finnic fricative *š in wordstems like:
-Finnish rohto 'medical plant, green herb' < PreFi *rošto <= PreG *groH-tu- > Gmc. *grōþu 'green growth' > Swedish grodd 'germ (shoot)'
-Old Finnish inhi-(m-inen) 'human being' < PreFi *inše- 'descendant' <= PIE *ģnh₁-(i)e/o- > Sanskrit jā́- 'born, offspring, descendant', Gmc. *kunja- 'generation, lineage, kin'
3) PIE laryngeals correspond to Pre-Finnic *k in wordstems like:
-Finnish kesä- 'summer' < PFU *kesä- <= PIE *h₁es-en- (*h₁os-en-/-er-) > Balto-Slavic *eseni- 'autumn', Gothic asans 'summer'
-Finnish kaski 'burnt-over clearing' < PreFi *kaske / *kaśke <= PIE/PreG *[h₂a(h₁)zg-] = */h₂e(h₁)sg-/ > Gmc. *askōn 'ashes'
-Finnish koke- 'to perceive, sense' < PreFi *koke- <= PIE *[h₃okw-ie/o] = */h₃ekw-ie/o/ > Greek opsomai ‘look, observe’ (cognate to Lat. oculus ‘eye’)
-Finnish kulke- 'to go, walk, wander' ~ Hungarian halad- 'to go, walk, proceed' < PFU *kulke- <= PIE *k^welH-e/o- > Greek pelomai ’(originally) to be moving', Sanskrit cárati 'goes, walks, wanders (about)’, cognate Lat. colere 'to till, cultivate, inhabit'
-Finnish teke- 'do, make' ~ Hungarian tëv-, të-, tesz- 'to do, make, put, place' < PFU *teke- <= PIE *d^heh₁> Greek títhēmi, Sanskrit dádhāti 'put, place', but 'do, make' in the western IE languages, e.g. the Germanic forms do, German tun, etc., and Latin faciō (though OE dón and into Early Modern English still sometimes means "put", and still does in colloquial German).

These examples represent but a few examples of the lexical borrowings found, especially when one also considers a number of etymologies with laryngeal reflexes in Finno-Ugric languages other than Finnish. For most cases no other plausible etymology exists. While some single etymologies may be challenged, the case for this oldest stratum itself seems conclusive from the Uralic point of view, and corresponds well with all that is known about the dating of the other most ancient borrowings and about contacts with Indo-European populations. Yet acceptance for this evidence is far from unanimous among Indo-European linguists, some even regard the hypothesis controversial.

Laryngeals in Morphology

Like any other consonant, Laryngeals feature in the endings of verbs and nouns and in derivational morphology, the only difference being the greater difficulty of telling what's going on. Indo-Iranian, for example, can retain forms that pretty clearly reflect a laryngeal, but there is no way of knowing which one.

The following is a rundown of laryngeals in Proto-Indo-European morphology.

*h₁ is seen in the instrumental ending (probably originally indifferent to number, like English expressions of the type by hand and on foot). In Sanskrit, feminine i- and u-stems have instrumentals in -ī, -ū, respectively. In the Rigveda, there are a few old a-stems (PIE o-stems) with an instrumental in -ā; but even in that oldest text the usual ending is -enā, from the n-stems.

Greek has some adverbs in -ē, but more important are the Mycenaean forms like e-re-pa-te "with ivory" (i.e. elephantē? -ě?)

The marker of the neuter dual was *-iH, as in Sanskrit bharatī "two carrying ones (neut.)", nāmanī "two names", yuge "two yokes" (< yuga-i? *yuga-ī?). Greek to the rescue: the Homeric form ósse "the (two) eyes" is manifestly from *h₃ekʷ-ih₁ (formerly *okʷ-ī) via fully-regular sound laws (intermediately *okʷye).

*-eh₁- derives stative verb senses from eventive roots: PIE *sed- "sit (down)": *sed-eh₁- "be in a sitting position" (> Proto-Italic *sed-ē-ye-mos "we are sitting" > Latin sedēmus). It is clearly attested in Celtic, Italic, Germanic (the Class IV weak verbs), and Baltic/Slavic, with some traces in Indo-Iranian (In Avestan the affix seems to form past-habitual stems).

It seems likely, though it is less certain, that this same *-h₁ underlies the nominative-accusative dual in o-stems: Sanskrit vṛkā, Greek lúkō "two wolves". (The alternative ending -āu in Sanskrit cuts a small figure in the Rigveda, but eventually becomes the standard form of the o-stem dual.)

*-h₁s- derives desiderative stems as in Sanskrit jighāṃsati "desires to slay" < *gʷhi-gʷhṇ-h₁s-e-ti- (root *gʷhen-, Sanskrit han- "slay"). This is the source of Greek future tense formations and (with the addition of a thematic suffix *-ye/o-) the Indo-Iranian one as well: bhariṣyati "will carry" < *bher-ḥ₁s-ye-ti.

*-yeh₁-/*-ih₁- is the optative suffix for root verb inflections, e.g. Latin (old) siet "may he be", sīmus "may we be", Sanskrit syāt "may he be", and so on.

*h₂ is seen as the marker of the neuter plural: *-ḥ₂ in the consonant stems, *-eh₂ in the vowel stems. Much leveling and remodeling is seen in the daughter languages that preserve any ending at all, thus Latin has generalized *-ā throughout the noun system (later regularly shortened to -a), Greek generalized -ǎ < *-ḥ₂.

The categories "masculine/feminine" plainly did not exist in the most original form of Proto-Indo-European, and there are very few noun types which are formally different in the two genders. The formal differences are mostly to be seen in adjectives (and not all of them) and pronouns. Interestingly, both types of derived feminine stems feature *h₂: a type that is patently derived from the o-stem nominals; and an ablauting type showing alternations between *-yeh₂- and *-ih₂-. Both are peculiar in having no actual marker for the nominative singular, and at least as far as the *-eh₂- type, two things seem clear: it is based on the o-stems, and the nom.sg. is probably in origin a neuter plural. (An archaic trait of Indo-European morpho-syntax is that plural neuter nouns construe with singular verbs, and quite possibly *yugeh₂ was not so much "yokes" in our sense, but "yokage; a harnessing-up".) Once that much is thought of, however, it is not easy to pin down the details of the "ā-stems" in the Indo-European languages outside of Anatolia, and such an analysis sheds no light at all on the *-yeh₂-/*-ih₂- stems, which (like the *eh₂-stems) form feminine adjective stems and derived nouns (e.g. Sanskrit devī- "goddess" from deva- "god") but unlike the "ā-stems" have no foundation in any neuter category.

*-eh₂- seems to have formed factitive verbs, as in *new-eh₂- "to renew, make new again", as seen in Latin novāre, Greek neáō and Hittite ne-wa-aḫ-ḫa-an-t- (participle) all "renew" but all three with the pregnant sense of "plow anew; return fallow land to cultivation".

*-h₂- marked the 1st person singular, with a somewhat confusing distribution: in the thematic active (the familiar -ō ending of Greek and Latin, and Indo-Iranian -ā(mi)), and also in the perfect tense (not really a tense in PIE): *-h₂e as in Greek oîda "I know" < *woyd-h₂e. It is the basis of the Hittite ending -ḫḫi, as in da-aḫ-ḫi "I take" < *-ḫa-i (original *-ḫa embellished with the primary tense marker with subsequent smoothing of the diphthong).

*-eh₃ may be tentatively identified in a "directive case". No such case is found in Indo-European noun paradigms, but such a construct accounts for a curious collection of Hittite forms like ne-pi-ša "(in)to the sky", ták-na-a "to, into the ground", a-ru-na "to the sea". These are sometimes explained as o-stem datives in -a < *-ōy, an ending clearly attested in Greek and Indo-Iranian, among others, but there are serious problems with such a view, and the forms are highly coherent, functionally. And there are also appropriate adverbs in Greek and Latin (elements lost in productive paradigms sometimes survive in stray forms, like the old instrumental case of the definite article in English expressions like the more the merrier): Greek ánō "upwards, kátō "downwards", Latin quō "whither?", eō "to that place"; and perhaps even the Indic preposition/preverb â "to(ward)" which has no satisfactory competing etymology. (These forms must be distinguished from the similar-looking ones formed to the ablative in *-ōd and with a distinctive "fromness" sense: Greek ópō "whence, from where".)

Pronunciation

Considerable debate still surrounds the pronunciation of the laryngeals and various arguments have been given to pinpoint their exact place of articulation. Firstly the effect these sounds have had on adjacent phonemes is well documented. The evidence from Hittite and Uralic is sufficient to conclude that these sounds were "guttural" or pronounced rather back in the buccal cavity. The same evidence is also consistent with the assumption that they were fricative sounds (as opposed to approximants or stops), an assumption which is strongly supported by the behaviour of laryngeals in consonant clusters.

*h₁

The assumption that *h₁ is a glottal stop [ʔ] is still very widespread. A glottal stop would however be unlikely to be reflected as a fricative in Uralic borrowings, as appears to be the case, for example in the word lehti < *lešte <= PIE *bhlh₁-to. If, as some evidence suggests, there were two *h₁ sounds, then one may have been the glottal stop [ʔ] and the other may have been the h sound [h] of English "hat".

*h₂

From what is known of such phonetic conditioning in contemporary languages, notably Semitic languages, *h₂ (the "a-colouring" laryngeal) could have been a pharyngeal or epiglottal fricative such as [ħ], [ʕ], [ʜ], or [ʢ]. Pharyngeal/epiglottal consonants (like the Arabic letter ح (ħ) as in Muħammad) often cause a-coloring in the Semitic languages. For this reason, the pharyngeal assumption is a strong one.

*h₃

Likewise it is generally assumed that *h₃ was rounded (labialized) due to its o-coloring effects. It is often taken to be voiced based on the perfect form *pi-bh₃- from the root *peh₃ "drink". Based on the analogy of Arabic, some linguists have assumed that *h₃ was also pharyngeal/epiglottal like Arabic ع (ayin, as in Arabic muعallim = "teacher") plus labialization, although the assumption that it was velar [ɣʷ] is probably more common. (The reflexes in Uralic languages could be the same whether the original phonemes were velar or pharyngeal.)

Possible similarities with the Semitic languages

Common assumptions or not, it is obvious that rounding alone did not color vowels in PIE; some additional (or alternative) feature like "lowered larynx" (as appropriate for "laryngeals" in the Semitic sense) might well have had the appropriate influence on the formants of adjacent vowels. It has been pointed out that PIE *a in verb roots, such as *kap- "take", has a number of peculiarites: it doesn't as a rule ablaut, and it occurs with noticeable frequency in roots like *kap-, viz., with a "plain velar" stop. But there is a chicken-and-egg problem here: if there is in fact any significance to this co-occurrence, does the plain velar articulation account for the a-vocalism, or vice-versa? At all events, if PIE *h₂ is regarded as somehow in the same series as the plain velar stops as usually reconstructed, it must be granted that its existence is considerably better founded than the existence of the plain velar stops.

The same is shown by some IE-Semitic correspondences, whether these are due to prehistoric borrowing or to a common ancestor (see Nostratic theory):-

Greek οδυσσομαι = "I hate", from IE root h₃-d-w :: Arabic عadūw = "enemy".
Greek αϝησι = "it (= a wind) blows", from IE root h₂-w-h₁ :: Arabic hawā' ="air".

A modern analogy

This theory requires the voiceless sound h₂ (ح ,ħ) to become a vowel. A modern (19th century AD) example of the same phonetic process is when the Sudanese Arabic placename 'Abu Tͅuleiħ أبو طليح (i.e. h₁abu tͅ(u)lēh₂) was rendered in contemporary British military records as Abu Klea.

References

Beekes, Robert S. P. (1969). The Development of Proto-Indo-European Laryngeals in Greek. The Hague: Mouton. no ISBN - Doctoral dissertation at the University of Leiden.
Beekes, Robert S. P. (1995). Comparative Indo-European Linguistics: An Introduction. Amsterdam: John Benjamins. ISBN 90-272-2150-2 (Europe), ISBN 1-55619-504-4 (U.S.).
Koivulehto, Jorma (1991). Uralische Evidenz für die Laryngaltheorie, Veröffentlichungen der Komission für Linguistik und Kommunikationsforschung nr. 24. Wien: Österreichische Akademie der Wissenschaften. ISBN 3-7001-1794-9.
Koivulehto, Jorma (2001). The earliest contacts between Uralic and Indo-European: Linguistic and Archeological Considerations. Helsinki: Mémoires de la societé Finno-Ougrienne 242. ISBN 952-5150-59-3.
Lindeman, Frederik Otto (1970). Einführung in die Laryngaltheorie. Berlin: Walter de Gruyter & Co. no ISBN - Sammlung Göschen.
Lindeman, Frederik Otto (1997). Introduction to the Laryngeal theory. Innsbruck: Intitut für Sprachwissenschaft der Universität Innsbruck.
Möller, Hermann (1911 reprint 1970). Vergleichendes indogermanisch-semitisches Wörterbuch. Göttingen: Vandenhoek & Ruprecht. no ISBN.
Rix, Helmut (1976). Historische Grammatik der Griechischen: Laut- und Formenlehre. Darmstadt: Wissenschaftliche Buchgesellschaft.
Szemerényi, Oswald (1996). Introduction to Indo-European Linguistics. Oxford: Clarendon Press.
Sihler, Andrew (1996). New Comparative Grammar of Greek and Latin. Oxford: Oxford University Press.
Winter, Werner, ed (1965). Evidence for Laryngeals, 2nd ed. The Hague: Mouton.