Sometimes when studying these languages, you just get worn down. You master one declension, turn the page, and some freakish apparition like fero, ferre, tuli, latum or fe/rw, oi)/sw, h)/neika leaps out at you. And you might get dispirited, and lose sight of why you're doing this in the first place.
But take heart!
You're not studying Old Irish!
Some quotes from Fortston's Indo-European Language and Culture (for the Unicode un-enabled, I use a circumflex ...