Editing Classical Arabic (section)

==== Barth-Ginsberg alternation ====
Proto-Central Semitic, Proto-Arabic, various forms of Old Arabic, and some modern Najdi dialects to this day have alternation in the performative vowel of the prefix conjugation, depending on the stem vowel of the verb. Early forms of Classical Arabic allowed this alternation, but later forms of Classical Arabic levelled the /a/ allomorph:
{| class="wikitable"
!
! colspan="2" |Pre-Classical (''taltalah'')
!Classical
|-
|1 sg.
|''ʾi-rkabu''
|''ʾa-qtulu''
|''ʾa-...-u''
|-
|2 m.sg.
|''ti-rkabu''
|''ta-qtulu''
|''ta-...-u''
|-
|3 m.sg.
|''ya-rkabu'' (< *''yi-'')
|''ya-qtulu''
|''ya-...-u''
|-
|1 pl.
|''ni-rkabu''
|''na-qtulu''
|''na-...-u''
|}