@Mushroom
And those are actually languages that many linguists study because they are still spoken almost exactly as they were thousands of years ago.
Well, true that Lithuanian and Latvian are studied as living fossils believed to be close to the very stem of Indoeuropean language tree, but I too wouldn't be understood thousand years ago, and while there's fair possibility I might have a headstart on picking up one or two of the small regional languages used here then, I would need some serious adjustment. Neither Latvian nor Lithuanian existed then as such, both being fusion products of prior fragmentation (and in Latvian case, throwing a now extinct finno-ugric language into the mix too).
While so often mentioned together, and probably sounding quite alike for foreigners, Lithuanian and Latvian aren't mutually intelligible at all although it is possible to morph the (archaic) core lexicon words between them with simple algorithmic application of phonetic transformations. Quite some of those words have further meaning and usage drifts though, so even that won't necessarily help all that much. And then of course there's those centuries Lithuanians were in union with Poland while Latvian was "kitchen" language under German (and after Russians beat Sweden peasants in Latvia would speak (proto-) Latvian between themselves, German to their landlords and Russian to the state administration).
Modern standard "middle" Latvian has some traits of artificial language (such as quite extreme regularity) because it is in a sense -- it's a late nineteenth century work by a small team of truly genius national linguists, systematized and half reinvented combination of prior dialects (of with only Latgalian survives, differing from standard Latvian more than some east-slavic languages between themselves; barely partially intelligible for a standard Latvian speaker and uses additional letters). The number of new words they introduced is mind blowing.
Soviet authorities extinguished the palatalized R with a decree (together with distinction between hard "ch" and soft "h" with was a good thing as it was the only case of silent "c" artificial and irregular and any "h" sound in standard Latvian is only encountered in loanwords anyway) and while it's true almost no one can pronounce that abomination correctly (I can't either, try to make R and Y from York at the same time) and it was used in just a handful of word roots, it's absence wreck subtle chaos to that system leading to irregularities like the half-joking that the world "dzert" [to drink] now has to be pronounced differently depending whether it's tee or alchohol to be drank.
(Letter "e" denotes both sounds "e" and "æ" with choice governed by strict rules that parse the world backwards, without the palatalized "rj" demanding the "narrow" "e" it becomes wide "æ" especially in first person present "dzeru" where it's encouraged by the wide "u" ending, or plural "dzeram" where "a" pretty much force it without narrowing sound between, but the original and formally correct narrow "e" survive in infinity and curiously even in first person past "dzēru / dzērām" where it's long, but that on itself is no formal reason for it not to be wide either, making the word uniquely irregular -- with may not sound like much for someone speaking something as chaotic as English, but is uncomfortable for a Latvian.)
Now Latvian face quite unique challenges as smallish language with formally dominant status in its native territory but relatively large numbers of non-native users both internally and abroad and managing significant numbers of "overseas" diaspora. North American Latvian, based on conservative derivative under heavy English influence, differs from the current normative both in phonetics and grammar (some of which, like dropping gendered surnames are forced by practicality). Even prior the pandemic we had ongoing program of distance learning aimed at global reintegration of diaspora (and thanks to that we could switch schools locally to distance learning rather easily).
Russian-native Latvian speakers are blind deaf and mute to the three intonation system and struggle mightily with even distinction between short and long vowels (curiously they try to find system in that, there's for a change none, inflections yes, but as used in word roots they're simply different letters, unrelated to accent or anything).
Meanwhile Latvia-Russian had become quite established dialect gathering research interest as abnormality (large language forming dialect under influence of much smaller), allegedly they form sounds differently from standard Russian and use Latvian sentence structures. And they're stuck here. Russia encourage "repatriation" but many who tried that believing the propaganda report open hostility from locals over there exactly because of the distinct accent immediately placing them. And it doesn't matter they're born native Russian speakers refused to learn Latvian and test for citizenship on ideological grounds, they sound like those hated "fascists" for the locals, and worse, act like Europeans and thus are enemy.