More like pet peeves, and not something I'd lose my sleep over, but they're hilariously pedantic. I'll focus on Latin because I'd rather not pick on existing linguistic communities.

⟨V⟩ and ⟨U⟩ are not different letters in Latin. Deal with it. The "right" way to use them is like this:

• Upper case - ⟨V⟩, always
• Lower case - ⟨u⟩ or ⟨v⟩, pick one, but don't mix them

People fāiling to follow the əbove ɑre æs ənnoying æs someone insistently respelling English ⟨A⟩ with rændom junk bāsed on the sound. Like I æm doing now.

Same deal with ⟨I⟩ vs. ⟨J⟩. J'm not gojng to stop you from dojng so, but you can almost hear my "tsk, tsk, tsk" from a djstance.

There's one way to pronounce Latin ⟨C⟩. It's /k/ (as in "skill"). If you use /tʃ/ (as in "chimp"), /ʃ/ (as in "shampoo"), /ts/ (as in "cats"), /s/ (as in "silly"), you're doing it wrong. Unless you're handling Late Latin, but then follow some consistent set of rules dammit, not just "I use Latin like the Church does".

"Veni, uidi, uici" is supposed to be pronounced ['we:ni: 'wi:di: wi:ki:]; or roughly "WAY-nee WEE-dee WEE-kee". Once you pronounce it with random stuff like "vany VD vaitchy", you're wrecking all its alliterative appeal.

Speaking on that, Brutus is an unsung hero for going all stab-stabby against the guy who said the above. A shame that nobody did it against his adoptive child.