More Lab Rats Language Headcanons
(Except it's mostly me freaking out about Lithuanian Kaz.)
Kaz is Lithuanian! Inspired by his name, which is the Lithuanian variant of the name Casimir. Interestingly enough, Casimir comes from "mir/u" [peace] and the other half could either stem from "kazać" [to preach] or "kazic" [to destroy]. Basically Kaz's name could either mean "bringer/preacher of peace" or "destroyer of peace". Symbolism!
Most Lithuanians are Catholic, thus why he has so many siblings
They immigrated to the US when Kaz was a baby. He can speak Lithuanian, specifically the western Aukštaitian dialect, but ONLY if he doesn't think about it. Oliver asks him how to say a word in Lithuanian, Kaz just shrugs, then has an entire conversation with his mom in the language.
EDIT: Kazys is a diminutive of Kazimieras, so his family calls him that.
Bridget definitely made him take French lessons as a child, so he knows basic French.
""Calderan"" doesnt exist the same way "Human" or "Terran" doesn't exist. I headcanon that Skylar & her kind, including the lava creatures that raised them, aren't actually native to Caldera. The lava creatures taught Skylarkind English, though over time it evolved into its own dialect with lots of loanwords/grammar from the native languages of Caldera. Earth is sort of the galactic hub of the universe, thus why the lava creatures chose English as their language.
It's Calderan humor to describe things as their complete opposite, i.e calling candy "diarrhea". Over time the jokes stopped being jokes and just became their name (like non-plussed, which means both "unsettled" and "undisturbed").
Speaks the most obscure languages in the world for no particular reason.
Horace speaks Old Castilian, Mexican Spanish, and Classical Arabic. He mashes them up in amusing ways.
Alan was raised thinking that's just How People Talk, and so will casually drop Spanish/Arabic words into conversation and then call people stupid when they don't understand. He also knows bits & bobs of a few alien languages.