The question is what time do you refer with "most Hungarian Jews were at
least bilingual", and what part of the country, and which community. 1930 a
book was published about Bekescsaba by Geza Korniss and Dr. Fulop Revesz
wrote one chapter about the history of the Jewish community. He wrote that
around 1840 the community grow, many of them came >from the counties
Trencsen, Arva, Lipto and Nyitra to Csaba becouse they had here less problem
with the "Tot (Slave)" language as with Hungarian. Bekescsaba was also
called Tatcsaba or possibly Totcsaba becouse of the Slowak minorities. The
first (lelkipasztor) rabbiwas Jozsef Hirschfeld, he couldn't speak Hungarian
and he preached also German. In 1861 Moritz Klein became teacher and writer
of minutes, he kept the records in Hungarian and when graf Pal Teleki died
he held the funeral oration in the synagogue in Hungarian. My grandmother
was religious, I couldn't say whether she spoke Jiddish, but none of her
sons spoke it, they were born before 1900. I asked two friends, who belonged
to the orthodox community of Csaba, but none of them spoke in their
childhood Jiddish. There might be a difference between ones living in the
Trianon part of the country and the ones in Slovakia, Carpatho Ukraina and
Transsylvania.

Best regards
Gabor Hirsch