These so-called "internal a" or "broken" plurals are securely attested in Semitic, Berber, Cushitic, and Chadic, although it is unclear if the Chadic examples are an independent development.
ðiːz sˌoʊkˈɔːld "ɪntˈɜːnəl ˈeɪ" ɔːɹ "bɹˈoʊkən" plˈʊɹɹəlz ɑːɹ sᵻkjˈʊɹli ɐtˈɛstᵻd ɪn sɛmˈɪɾɪk, bˈɜːbɚ, kʊʃˈɪɾɪk, ænd tʃˈædɪk, ɔːlðˈoʊ ɪɾ ɪz ʌŋklˈɪɹ ɪf ðə tʃˈædɪk ɛɡzˈæmpəlz ɑːɹ ɐn ˌɪndᵻpˈɛndənt dɪvˈɛləpmənt.