quoting my friend:

College Yiddish is a classic, but I'm also a big fan of Sheva Zucker's two-part Yiddish textbooks.
DeRijk, if that counts as a textbook, and Alan R. King's Elementary Basque or whatever it's called.

Genki is a beloved Japanese textbook for a reason, though I haven't used it much. I'm also a big fan of Learn Japanese the Manga Way, which is better as a reference text but is still really good either way.