,,Chmm"
,,Zarya, Pank Treicer [probably Punk Tracer],"
The last bubble probably ,,Are you laughing, keksik [biscuit in my language, no idea what it means in this <not sure if it's neccesarily Russian>]? Seemingly/evidently I... something... Nastoyashchaya..."
Okay found out how to write it into translate. So the biscuit thing is probably euphemism like honey.
,,Are you laughing, honey? It's clear I am the real one!"
,,Well, I don't know... I'd need you to take off shirts..." or something like that
EDIT: Jeddy017 below said:
I read an English version of this before. Cait is trying to find out which one is Vi. Vi says something along the line, " This is ridiculous, it's obviously me."
And Cait is still skeptical & says they need to take off their shirts.
which is a good point. Something along lines of "laughable" can be used in some slavic languages with meaning of ridiculous. As in "These accusations are laughable/ridiculous, you can't mean them seriously". So it's highly possible "[Are] You Laughing?" is a phrase meaning "This is ridiculous".
Also, by what LiptonSwagger below reminded, it's possible it should be cupcake instead of honey, pointing to Cait's Yordle Trap as her "nickname".