The education in 20s and 30s germany was not really that heavily effected by the economy crisis. It just was usual, especially in rural areas, that there is one teacher living in the schoolhouse teaching children of all classes simultaneously. Which would otherwise hardly be effective, as there were usually not more than ~30-40 children at one school. Remember that back then kids would have hardly be able to jump a bus and drive to a central school with more than 1000 students like 10kms away, as its common today.
Yet, foreign languages just had no real eligibility in the curriculums back then. Why should they? English was, in comparison with today, completely unneccessary. Today it's quite usual here to learn french as second language, but back then france was the arch enemy.
So, at standard schools for kids that were to learn a standard job later, none would usually learn a foreign language.
Of course, grammar schools for kids who wanted to go to university did teach foreign language. A LOT, actually. But this was usual latin and ancient greek, following old humanist ideals, with latin being the international language of science (back then, till it got somewhat superseded by german, which was then replaced by english). Remember that those languages were considered the fundament of european culture, which to a certain degree is absolutely correct. Plus these languages pose a wide range of grammatics to learn, which is however quite logically structured (at least Latin, I don't know ancient greek) and hence was regarded useful to cultivate the students education.
The german education only grew REALLY poor during the wars. My grandmother used to tell me how happy she was seeing me learn so much and being able to tell her so much, as she was so curious as a child - but in her time in school (~1937 or 38 till about 1944 or 45) they spent most of there time gathering beechnuts for oil or blueberries in the forest, sewing socks for soldiers, they were provided to the local noble landlords estate as seasonal workers etc. pp.