There are 10 vowel phonemes in Czech. 5 of them are short and 5 are long. The duration of the long vowels is approximately double in comparison with their short counterparts. Long and short vowels form minimal pairs. The length (quantity) is an important distinctive feature in Czech. It differentiates various word meanings, e.g. pata /pata/ (heel) x pátá /paːtaː/ (the fifth). Moreover, some authors regard the diphthongs as separate phonemes.
The Czech vowel system is three-grade and triangular (see the picture). The system of long vowels is regarded as symmetric with the system of short vowels, although the phoneme /oː/ occurs almost exclusively in words of foreign origin.
Besides the length, the distinctive features of vowels are the openness (open/mid/close) and the frontness/backness (front/central/back). The roundedness is not a separate distinctive feature, it enlarges the acoustic difference between the front and the back vowels. The back vowels are rounded while the front and central ones are unrounded.
Vowel modifications such as nasalization do not occur in Czech. The vowels are never reduced and undergo no assimilations. The vowel length and quality is independent of the stress.
Long vowels are indicated by an acute accent or a ring.
The phonemes /o/ and /oː/ are sometimes referred as /ɔ/ and /ɔː/. This transcription describes the pronunciation in Central Bohemia and Prague, which is more open. The standard pronunciation is something between [o(ː)] and [ɔ(ː)], i.e. mid back vowel.
Note that ě is not a separate vowel. It simply denotes [{IPA|/ɛ/}} after a palatalized consonant and a preceding {{IPA|/j/}] after hard consanats (labials, velars): bě /bjɛ/.
There are three diphthongs in Czech:
Vowel groups ia, ie, ii, io, and iu in foreign words are not regarded as diphthongs, they are pronounced with /j/ between the vowels .
The following chart shows a complete list of the consonant phonemes of Czech:
| Bilabial | Labio- dental | Alveolar | Post- alveolar | Palatal | Velar | Glottal | |
|---|---|---|---|---|---|---|---|
| Nasal | m | n | ɲ | ||||
| Plosive | p b | t d | c ɟ | k g | |||
| Affricate | ts dz | tʃ dʒ | |||||
| Fricative | f v | s z | ʃ ʒ | x | ɦ | ||
| r̝ | |||||||
| Trill | |||||||
| r | |||||||
| Approximant | l | j |
The phoneme /r̝/ (written as <ř>) is an alveolar fricative trill (see alveolar trill); its rarity makes it difficult to produce for foreign learners of Czech. The basic realization of this phoneme is voiced, but it is voiceless [r̝̊] when preceded or followed by a voiceless consonant or at the end of a word. (Listen: Antonín Dvořák )
The phoneme /ɦ/ is voiced glottal fricative [ɦ]. Its voiceless realization is velar [x].
Secondary articulations (aspiration, labialization, velarization, palatalization, etc.) are not used in Czech.
The glottal stop is not a separate phoneme. Its use is optional and it may appear as the onset of an otherwise vowel-initial syllable. The pronunciation with or without the glottal stop does not affect the meaning and is not distinctive.
The glottal stop has two functions in Czech:
In the standard pronunciation, the glottal stop is never inserted between two vowels in words of foreign origin, e.g. in the word koala.
| IPA | Czech alphabet |
|---|---|
| /ʃ/ | š |
| /ʒ/ | ž |
| /ɲ/ | ň |
| /c/ | ť |
| /ɟ/ | ď |
| /ɦ/ | h |
| /x/ | ch |
| /ts/ | c |
| /tʃ/ | č |
| /dʒ/ | dž |
| /r̝/ | ř |
Realizations of consonant phonemes are influenced by their surroundings. The position of phonemes in words can modify their acoustic realizations without a change of the meaning.
These assimilations are optional. Realizations as [tramvaj] or [banka] are possible, especially in more prestigious registers.
Assimilation of voice is an important feature of Czech pronunciation. Voiced obstruents are, in certain circumstances, realized voiceless and vice versa. It is not represented orthographically where more etymological principles are applied. Assimilation of voice applies in these circumstances:
Voiced and voiceless obstruents form pairs in which the assimilation of voice applies (see table):
| Voiceless | Voiced |
| [p] | [b] |
| [t] | [d] |
| [c] | [ɟ] |
| [k] | [ɡ] |
| [f] | [v] |
| [s] | [z] |
| [ʃ] | [ʒ] |
| [x] | [ɦ] |
| [t͡s] | [d͡z] |
| [t͡ʃ] | [d͡ʒ] |
| [r̝̊] | [r̝] |
Sonorants (/m/, /n/, /ɲ/, /j/, /r/ and /l/) have no voiceless counterparts and are never devoiced. They do not cause the voicing of voiceless consonants in standard pronunciation, e.g. sledovat [slɛdovat] (to watch).
There are some exceptions to the rules described above:
Two identical consonant phonemes (or allophones) can meet in morpheme boundaries during word formation. In many cases, especially in suffixes, two identical consonant sounds merge in one sound in the pronunciation, e.g. cenný (valuable), měkký (soft).
In prefixes and composite words, doubled pronunciation (gemination) is obvious, i.e. both phonemes are pronounced separately. It is necessary in cases of different words: nejjasnější [nɛjjasɲɛjʃiː] (the clearest, the brightest) x nejasnější [nɛjasɲɛjʃiː] (more unclear). Doubled pronunciation is perceived as hypercorrect in cases like [t͡sɛnniː] or [mɲɛkkiː].
Combinations of plosives and fricatives usually produce affricates (): dětský [ɟɛt͡skiː] (child’s). Both phonemes are pronounced separately in careful pronunciation: [ɟɛt.skiː].
Consonant merging is perceived as careless at word boundaries, e.g. pojď sem (come here) realized as [pot͡sɛm]. It is necessary to pronounce all phonemes clearly and separately: [pojc.sɛm].
The stress is always fixed to the first syllable of a word. The exceptions are following:
Long words can have the secondary stress which is usually placed on every odd syllable, e.g. ˈnej.krás.ˌněj.ší (the most beautiful).
The stress has no lexical or phonological function; it denotes boundaries between words but does not distinguish word meanings. It has also no influence on the quality or quantity of vowels, i.e. the vowels are not reduced in unstressed syllables and can be both short and long regardless of the stress. Thus, the Czech rhythm can be considered as isosyllabic.
Czech is not a tonal language. Tones or melodies are not lexical distinctive features. However, intonation is a distinctive feature on the level of sentences. Tone can differentiate questions from simple messages, as it need not necessarily be indicated by the word order:
All these sentences have the same lexical and grammatical structure. The differences are in their intonation.
The general structure of Czech syllables is:
Thus, Czech word can have up to four consonants in the initial group and three consonants in the final group (not including syllabic consonants). The syllabic nucleus is usually formed by vowels or diphthongs, but in some cases syllabic sonorants (/r/ and /l/, rarely also /m/) can be found in the nucleus, e.g. vlk [vl̩k] (wolf), krk [kr̩k] (neck), osm [osm̩] (eight).
Vowel groups can occur in the morpheme boundaries. They cannot include more than two vowels. Both vowels in the groups are separate syllabic nuclei and do not form diphthongs.
| Short phoneme | Long phoneme | Examples, notes |
|---|---|---|
| /a/ | /aː/ | (founder) – (to found) |
| /ɛ/ | /ɛː/ | letadlo (airplane) – létat (to fly) |
| /ɪ/ | /iː/ | litovat (be sorry) – lítost (regret) vykonat (to perform) – výkon (performance) |
| /o/ | /uː/ | koně (horses) – (horse) |
| /ʊ/ | /uː/ | učesat (to comb) – účes (hair style) (in initial positions in morphemes only) |
| /ʊ/ | /oʊ̯/ | kup! (buy!) – koupit (to buy) (in other positions) |
Some other disjunctive vowel alternations occur in word roots during derivations (rarely also during inflections):
Emergence/disappearance alternations also take place, i.e. vowels alternate with null phonemes. In some allomorphs, /ɛ/ is inserted between consonants in order to make the pronunciation easier:
It also occurs in some prepositions which have vocalised positional variants: v domě – (in a house) – ve vodě (in water); s tebou (with you) – se mnou (with me), etc.
Some other alternations of this type occur, but they are not so frequent:
| Hard | Soft | Examples, notes |
|---|---|---|
| /d/ | /ɟ/ | (young – masc. sg.) – (young masc. anim. pl.) |
| /t/ | /c/ | plat (pay, wages) – platit (to pay) |
| /n/ | /ɲ/ | žena (woman) – ženě (woman – dat.) |
| /r/ | /r̝̊/ | (good – adj.) – (good – adv., well) |
| /s/ | /ʃ/ | učesat (to comb) – učešu (I will comb) |
| /z/ | /ʒ/ | ukázat (to show) – ukážu (I will show) |
| /t͡s/ | /t͡ʃ/ | ovce (sheep) – ovčák (sherpherd) |
| /g/ | /ʒ/ | Riga – rižský (adj.) |
| /z/ | v Rize (in Riga) | |
| /ɦ/ | /ʒ/ | Praha (Prague) – Pražan (Prague citizen) |
| /z/ | v Praze (in Prague) | |
| /x/ | /ʃ/ | prach (dust) – prášit (to raise dust) |
| /s/ | smíchat (to mix) – směs (mixture) | |
| /k/ | /t͡ʃ/ | (wolf) – vlček (little wolf) |
| /t͡s/ | vlci (wolves) | |
| /sk/ | /ʃc/ | britský (British – masc. sg.) – britští (British –masc. anim. pl.) |
| /t͡sk/ | /t͡ʃc/ | anglický (English – adj.) – angličtina (English – language) |
| /b/ | /bj/ | nádoba (vessel) – v nádobě (in a vessel) bílý (white) – bělásek (cabbage white butterfly) |
| /p/ | /pj/ | zpívat (to sing) – zpěvák (singer) |
| /v/ | /vj/ | tráva (grass) – na trávě (on the grass) vím (I know) – vědět (to know) |
| /f/ | /fj/ | harfa (harp) – na harfě (on the harp) |
| /m/ | /mɲ/ | dům (house) – v domě (in a house) smích (laughter) – směšný (laughable) |
The last four examples are emergence alternations. A phoneme (/j/ or /ɲ/) is inserted in the pronunciation, but for the historical reasons, these changes are indicated by <ě> in the orthography (see the orthographic notes below). These alternations are analogical with softening alternations, therefore they are mentioned here. They also occur in word roots together with vowel alternations (usually |ɛ/iː|).
Some other alternations occur but they are not so frequent. They are often little evident:
In some letter groups, phonological principles of the Czech orthography are broken:
| Voiced | Voiceless | Nasal |
|---|---|---|
| dy [dɪ] | ty [tɪ] | ny [nɪ] |
| di [ɟɪ] | ti [cɪ] | ni [ɲɪ] |
| dí [ɟiː] | tí [ciː] | ní [ɲiː] |
| dě [ɟɛ] | tě [cɛ] | ně [ɲɛ] |
| bě [bjɛ] vě [vjɛ] | pě [pjɛ] fě [fjɛ] | mě [mɲɛ]
|