I'm Campbell Nilsen, and I'm a high-school student who's been studying Old
Irish on and off for some time. (I'm really fascinated by obscure languages.)
The introduction having been given, here's my question.
Looking through the prehistory of Old Irish declensions (I have Sengoidelc, and
a wonderful tome it is), it seems to me that the nominative singular of
masculine o-stems should produce an aspiration mutation. In Primitive Irish, for
example, the nominative singular of what became 'ech', "horse", was 'eχwah'
(using w for u-with-undercurve, because I can't find that symbol). 'Ech'
produces no mutation. But the accusative plural is 'echu', with an aspiration
mutation. In Prim. Irish, it too had an -h at the end. So what's going on,