Igbo Language Vowel Assimilation and Vowel Elision (olilo ụdaume, ndapụ ụdaume, ndapụ mgbochiụdaume)

Igbo Vowel Assimilation, Vowel Elision and Consonant Elision
The Igbo terms for vowel assimilation is olilo ụdaume, vowel elision is ndapụ ụdaume and consonant elision is ndapụ mgbochiume.

Igbo Vowel Assimilation
Vowel assimilation is where one vowel drops its sound and adopts the sound of the vowel that immediately precedes it or it immediately precedes. Vowel assimilation happens only in pronunciation, the words are not necessarily written as they sound.

onye isi sounds onyi isi in pronunciation when said at a normal speech pace.
onye - one, someone, person
isi - head, top, source, main
onye isi means chairman or one who heads..... [school, church, police, meeting, etc.]

Vowel Elision
Vowel elision is where a vowel drops out, and the vowel that immediately precedes it or it immediately precedes is enough to convey the desired meaning. Vowel elision happens in pronunciation, and can be written as they sound.

nwa oke sounds nwoke in pronunciation. The vowel 'a' drops out.
nwa - one/of
oke - male
nwoke means man

Consonant Elision
In consonant elision, consonant sounds are is omitted in conversation. The consonants are not omitted when written.

ọ bụ onye na-ekwu becomes ọ ọ onye neekwu (who is speaking). The consonant 'b' was dropped in the conversation. Note that there is also vowel assimilation from na-ekwu to neekwu.
kedụ ihe ọ bụ becomes kee ihe ọ ọ (what is it)
ọ nọghị ya becomes ọ nọọ ya (he is not around)
e meghị m ya becomes e mee m ya (I didn't do it)

As a side note
Some of the words we know today might have come to us through assimilation and elision. For example, we have names like Akosa (Aka Olisa), Osakwe (Olisa kwe), Ononye (ọ bụrụ na onye?)