I speculate that if one were to subdivide a population of “general German immigrants” based upon any ad hoc cultural basis, differential levels of educational experience, degrees of social integration, along with a myriad of other differences, cultural and otherwise would likely enter into the results so much so as to skew the analysis.
Additionally, I speculate that any mild rule for subdivision based upon such simple criteria (Jewish vs. non-Jewish) would likely be *noisy* (statistically speaking) and have many unexpected associations coloring the information obtained.
For instance, I have often heard that color-blindness is more prevalent in Irish-Americans (and Scottish-Irish in Scotland and consequently is now less common in the Irish in Ireland) because those who were color-blind were unable to distinguish good seed potatoes from blighted seed potatoes (which would rot in the ground rather than produce more potatoes or produce potatoes that would turn to mush minutes after harvest) and that these color-blind emigrated from Ireland during the Irish Potato Famine of “...between 1845 and 1852...” (wikipedia but I have also heard that the blight extended until 1857 or so)
Here is a supportive link:
...People with this form of color blindness could not tell the difference between blighted potatoes and normal potatoes. Such people used blighted potatoes as seed for next year’s crop, resulting in a disastrous crop the next year. These were the first Irish to emigrate from Ireland due to the famine caused by the potato blight…
(Please note: this link/quote is a blog/forum post and thus far from definitive. This could yet be a myth. I haven’t found a definitive source and it’s a hard one to google search because “color-blind” has become a much-used and socially-charged word recently...)
So possibly, if one were to have tried looking at Irish-Catholic vs Irish-Protestant related words entering the language of the places these color-blind Irish emigrated to, one might be looking at (in part) information *encoded* by virtue of color-blindness (collaterally related to educational level, poverty, or other seemingly cultural distinctions) when one may have been expecting to be only looking at differential relationships between “Irish-Catholic” vs. “Irish-Protestant” words.
I think “widespread adoption of this German term [gesundheit] in the USA” is likely more related to other cultural factors. German emigrants spoke German. Some Jews spoke German. Some Jews were German immigrants. Some German immigrants were not Jews. OP, have you discovered a somehow particularly Jewish-related etymology?
Etymonline suggests:
...1914, from Ger. Gesundheit, lit. “health!” Also in toast auf ihre Gesundheit “to your health” (see sound (adj.)). Lith. aciu, echoic of the sound of a sneeze,…
[and, for the word, ”sound” (from the same above etymonline link):]
..."uninjured," O.E. gesund “sound, safe, healthy,” from P.Gmc. *sundas, from root *swen-to- (cf. O.S. gisund, O.Fris. sund, Du. gezond, O.H.G. gisunt, Ger. gesund “healthy,” source of the post-sneezing interjection gesundheit; also O.E. swið “strong,” Goth. swinþs “strong,” Ger. geschwind “fast, quick")…
I did find this:
Gesundheit (g’-SUND-hahyt)
Yiddish. Literally, health. This is the normal response when somebody sneezes. The same expression is used in German (Yiddish is largely based on German), and is quite common even among non-Jews,…
When Jews sneeze…
...The Talmud (Berachot 53a) states that in the time of Rabban Gamliel (1st century) it was the practice to say “Marpeh” (Hebrew for “healing") to someone who sneezed. The commentary of Rashi (11th century) adds that the equivalent Aramaic word, “Asuta,” was also used, and the 16th-century Code of Jewish Law (Orach Chaim 170:1) cites this as the normative practice. (None of these sources say that one should say this; they just mention incidentally in the course of discussion that this was done.)…