The use of the nasalisation-mark has also been strictly limited in the case of nasalised vowels preceding ʋ̃. Not every vowel preceding ʋ̃ is nasalised: in the following cases they have little or no nasalisation― (1) in nominal prefixes, such as u-ʋ̃ɛ [ ˩ \ ] “salt”, ɔ-ʋ̃a [ ˩ \ ] “man”; (2) conjunctive pronouns, e.g. i-ʋ̃ɛ [ ˩ / ] “I have”; (3) originally unnasalised verbal stems in nouns of action of the type prefix u＋stem ＋ʋ̃ɛ, e.g. ukɔʋ̃ɛ [ ˩ \ ˩ ] “act of planting”. In all other cases, vowels preceding ʋ̃ within the same word are nasalised. As ʋ̃ is rather frequent in the nominal and verbal suffix -ʋ̃ɛ (assimilated -ʋ̃a, -ʋ̃i, -ʋ̃ɔ, -ʋ̃u), the omission of the tilde (～) goes a long way towards simplifying the appearance of the written word, and it should not be difficult to remember in which words the vowel is nasalised if the above rule is kept in mind.
It is, however, necessary to mark nasalisation in originally nasalised vowels of verbal stems occurring in nouns of action of the type prefix u ＋stem＋ʋ̃ɛ, e.g. ukɔ̃ʋ̃ɛ [ ˩ \ ˩ ] “foolishness”. (This word is derived from kɔ̃ [ ˥ ] “to be foolish”, while the above-mentioned ukɔʋ̃ɛ is derived from kɔ [ ˥ ] “to plant”.)
The following diphthongs occur in Bini: ia, ie, iɛ, io, iɔ, ua, ue, uɛ, uo, uɔ, ae, ɔe, oi, and the nasalised ones iã, iɛ̃, iɔ̃, uã, uɛ̃, uɔ̃, aɛ̃, ɔɛ̃, oĩ.
The triphthongs in Bini are iae, iɔe, ioi, uae, uɛe, uɔe, uoi; and the nasalised ones iaɛ̃, iɔɛ̃, uaɛ̃, uɔɛ̃. Here, also, nasalisation is not marked after nasals.
Initial i and u are often semi-vowels, especially in other than very slow speech; final e, ɛ̃, i are usually very short; in triphthongs the middle part is usually the most prominent.
CONSONANTS
The plosives p, t, k (slightly aspirated) and b, d, g need no comment, nor do the labio-dental fricatives f and v.
ʋ is a voiced bilabial fricative (written vb in literature already published).
ʋ̃ is a nasalised bilabial fricative. It is a separate nasal phoneme, distinct from ʋ and m (mw in literature already published).
s and z are sometimes heard palatalised, e.g. in the speech of J. U. Egharevba. s and z are substituted for Yoruba ʃ and j, and English ch, sh and j in loan-words. There is evidence, however, that the more advanced section of the community do pronounce English ch and j in modern importations. The affricates j (dy) and dʒ occur, however, in onomatopoeic words.
There are two l-phonemes, one being the English “clear” l, and the other a flapped variety, ɽ, which is a sound intermediate between r and l; this has not been distinguished from r in existing publications, though some Bini speakers are conscious of this inadequacy.
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