On the interwebs, I recently confidently stated tiomáineann mé as a viable form, but was told it was not. Going to my books, I piced the Uladh version of An Teanga Bheo, which showed the analytical form, but was then told it was not proof of it for that very verb.

Given the mixed analytical/synthetic nature of the Irish verb, it sounds very natural and plausable to me.

Would Lughaidh care to add his bit?

_________________
__̴ı̴̴̡̡̡ ̡͌l̡̡̡ ̡͌l̡*̡̡ ̴̡ı̴̴̡ ̡̡͡|̲̲̲͡͡͡ ̲▫̲͡ ̲̲̲͡͡π̲̲͡͡ ̲̲͡▫̲̲͡͡ ̲|̡̡̡ ̡ ̴̡ı̴̡̡ ̡͌l̡̡̡̡.___

Actually I heard mostly the -(a)im ending but the Donegal Irish I heard is mainly Gaoth Dobhair, Rann na Feirste, and Cloich Cheannaola.
Now, I remember having read that the -(e)ann mé ending does exist - read this in An Teanga Bheo, I think, and also in Grammar of Ros Goill Irish Co. Donegal, by L. Lucas.
So, it's not wrong!
But learners tend to overuse it because it's "simpler", although it's not normal except if they want to speak northern Donegal Irish, and especially northeastern Donegal Irish

_________________
Is fearr Gaeilg na Gaeltaċta ná Gaeilg ar biṫ eile
Agus is í Gaeilg Ġaoṫ Doḃair is binne

Thanks, lad!

_________________
__̴ı̴̴̡̡̡ ̡͌l̡̡̡ ̡͌l̡*̡̡ ̴̡ı̴̴̡ ̡̡͡|̲̲̲͡͡͡ ̲▫̲͡ ̲̲̲͡͡π̲̲͡͡ ̲̲͡▫̲̲͡͡ ̲|̡̡̡ ̡ ̴̡ı̴̡̡ ̡͌l̡̡̡̡.___