I don't quite understand the "not changed in sound" part.
AFAIK, "lox" came to English through Yiddish, which got the word from German. And in German, the vowel was always "a" not "o" (e.g. https://ia600301.us.archive.org/32/items/etymologisches00klu... traces the word to "lahs"), so the vowel quality and the final consonant appear to have changed.
Indeed, the Modern English descendant of the Old English cognate word (still present today as a Scottish dialect word for "salmon", supposedly), would be "lax" - https://www.etymonline.com/word/lax
The consonants are the same, but whether the vowels are the same depends on your accent. In most British accents the vowel in 'lox' is fairly distinct from that in German 'lachs'. (Or I should probably say 'would be', since it's not a word known to most British English speakers.)
There are (at least?) three different ways "ch" can be pronounced in German: Throaty as in "Buch", a slightly altered "sh" sound like in "Bücher", and just as plain "k", like in "Lachs".
I was very surprised to see wiktionaries phonetic transcription and sound sample of "Buch", apparently it is not throaty everywhere.
It's a /k/ in all "-achs", e.g. "Dachs", "wachsen", "Flachs", exactly as in "bochs" the emulator (compare "boxen"), except across boundaries, e.g. "wachsam, wach-sam" (wakeful, at guard), or contractions, e.g. "[Meister seines].Faches/Fachs".
There is something puzzling about the existance/presevation of the word in Tocharian B. The tocharian people were living in the tarim basin, a dry land, far away from any ocean. Were there any salmons there?
The Tocharians used an Indic script. We know what the letters mean for Indic languages, so we can get a pretty good idea of what Tocharian sounded like. Pretty good.
Not perfect, though. For example, Icelandic and Old Norse are very close in terms of how they're written, but (IIRC) have pretty substantial differences in pronunciation.
Yep. It's likely that Icelandic speakers can read Old Norse, especially with footnotes, but they most likely wouldn't be able to understand the sagas if they were spoken aloud. And a lot of the reason Icelandic is as conservative as it is is because of a push towards purism from Danish influences in the 19th century.
All the Scandinavian languages can be read by speakers of the other Scandinavian languages, somewhat accuately, in written form, given enough time, cursing and crying is invested into doing it. Icelandic and Faraoese are quite different from the others, but they're not THAT hard to understand when written down.
Speakers of Danish, Norwegian and Swedish can usually talk to eachother without major issues although the kids seem to be preferring to speak English nowadays.
Spoken Icelandic or Faraoese on the other hand? I usually manage to get a single word or phrase. The rest is gibberish.
The General American pronunciation of lox is /lɑks/ [1], the Standard German pronunciation of Lachs is /laks/ [2]. Those vowels are not the same; the American one is further back. In other dialects of English, it would also be rounded and/or less open.
And the dictionary of the Swiss German language (which in many ways resembles Yiddish more than Standard German does), says that the spelling used to be "Lächs", which probably means that the vowel used to be brighter than it is today: https://digital.idiotikon.ch/idtkn/id3.htm#!page/31041/mode/...
I don't see in the article where it says the word hasn't changed, or anything about 8k years as claimed in the post title. It does say that "lox" happens to be composed of sounds that "haven't changed in English", which I take to mean that that English pronunciation in English hasn't changed during the time that the word has existed as part of the language. I don't believe the article claims that the pronunciation is unchanged across different languages.
You have it exactly opposite. Despite the fact that it is a recent addition to English via Yiddish, the pronunciation and meaning is unchanged for thousands of years.
You could go to the Eurasian steps in 3000 BC and ask for lox and they will know exactly what you mean.
AFAIK, "lox" came to English through Yiddish, which got the word from German. And in German, the vowel was always "a" not "o" (e.g. https://ia600301.us.archive.org/32/items/etymologisches00klu... traces the word to "lahs"), so the vowel quality and the final consonant appear to have changed.