Rotokas is a language (part of the East Papuan language phylum) spoken by some 4000 people in Bougainville, an island to the east of New Guinea, part of Papua New Guinea. There are at least three dialects of the language: Central Rotokas ("Rotokas Proper"), Aita Rotokas, and Pipipaia. Central Rotokas is most notable for its extremely small phonemic inventory and for having perhaps the smallest modern alphabet.
The three voiced members of the Central Rotokas dialect consonant phoneme inventory each have wide allophonic variation. Therefore, it is difficult to find a choice of IPA symbols to represent them which is not misleading. The total consonant inventory embraces the following places of articulation: bilabial, alveolar, and velar, each with a voiced and an unvoiced phoneme. The voiceless consonants are straightforward as plosive [p, t, k]; there is an alveolar allophone [ts]~[s], but this only occurs before [i]. The voiced consonants are the allophonic sets , , and .
It is unusual for languages to lack nasal phonemes. Firchow & Firchow (1969) have this to say on the lack of nasal phonemes in the Central Rotokas dialect (which they call Rotokas Proper):
In Rotokas Proper [...] nasals are rarely heard except when a native speaker is trying to imitate a foreigner’s attempt to speak Rotokas. In this case the nasals are used in the mimicry whether they were pronounced by the foreign speaker or not.
Robinson (2006) shows that in the Aita dialect of Rotokas there is a three-way distinction required between voiced, voiceless, and nasal consonants. Hence, this dialect has nine consonant phonemes versus six for Rotokas Proper. The voiced and nasal consonsants in Aita are collapsed in Central Rotokas, i.e. it is possible to predict the Central Rotokas form from the Aita Rotokas form, but it is not possible to predict the Aita form from the Central form. This shows that the phoneme inventory of the ancestor language of Aita and Central Rotokas was more like Aita, and that the small phoneme inventory in "Rotokas Proper" is a more recent innovation.
There does not seem to be any reason for positing phonological manners of articulation (that is, fricative, approximant, tap, stop, lateral) in Central Rotokas. Rather, a simple binary distinction of voice is sufficient.
When an [l] and [r] are given as variants, without their being determined by their environment, it's likely that they are actually either a lateral flap, [ɺ], or else a flap that is phonologically unspecified as to centrality (that is, neither specifically [ɾ] nor [ɺ], as in Japanese), and that the linguist has mistranscribed the sound.
Since a phonemic analysis is primarily concerned with distinctions, not with phonetic details, the symbols for voiced stops could be used: plosive [b, d, g] for Central Rotokas, and nasal [m, n, ŋ] for Aita dialect. (In the proposed orthography for Central Rotokas, these are written v, r, g. However, b, d, g would work equally well.) In the chart below, the most frequent allophones are used to represent the phonemes, without a decision being made on the laterality of the flap.
Vowels may be long (written doubled) or short. It is uncertain whether these represent ten phonemes or five; that is, whether 'long' vowels are distinct speech sounds or mere sequences of two vowels that happen to be the same. Other vowel sequences are extremely common, as in the word upiapiepaiveira.
Typologically, Rotokas is a fairly typical verb-final language, with adjectives and demonstrative pronouns preceding the nouns they modify, and postpositions following. Although adverbs are fairly free in their ordering, they tend to precede the verb, as in the following example:
|"The old woman's eyes are shut."|