Elliott Lash wrote:
> attoberthar could be a-tob-berthar where a- would be the
> correct form for a number of preverbs before class c and b: <ad, in,
> as>. Of course, the preverb should be <do>, but it sometimes
> happens in Middle Irish that preverbs interchange with each other.
Yep. The coalescence of ad-, aith-, ess-, in-, ind- as
undifferentiated at- in class B was something I thought of. But none
of those seemed to be likely preverbs, and do- is covered there, at
least in proper OI. Ah well.