“hooche Leit” is PA dialect for standard German “hohe Leute,” literally “high people” in the sense of “fancy” people as opposed to plain people, as there used to be “plain Dutch” and “fancy Dutch” to refer to plain (Anabaptist) Pennsylvania Germans as opposed to other (now basically assimilated) German people in Pennsylvania. Commonly what her community and many other Deitsch-speaking communities call “hooche Leit” in Deitsch, they will often simply call “English” in English. From her description that’s probably fallen mostly out of use in her Libby community given their religious abandonment of the Ordnung.

The etymological sense of the Pennsylvania Dutch phrase is in fact, as far as I can tell, 'high people' or 'fancy people'. This is not the literal meaning or connotation of the phrase in Pennsylvania Dutch today. I did not think (and the LLM did not claim) that the phrase is used in Pennsylvania Dutch with this meaning, or that it was borrowed from standard German at any time. Essentially, the LLM helped me find recognizable cognates to understand how the phrase originated.