Hey, my Friend!
I don't know about the other regions of Hungary, but in the South-western region, parts of Somogy, where german-based people were common in 1900's, there are very few left. I lived in a village, which was once home of almost 300 german-speaking people, along 300-700 people, who spoke hungarian only. Now the village has only 270 inhabitants, with only 2-3 families, who speak german, i mean, not the taught one, but which they learned from their ancestors. Their names were Kachstettner, Loósz, Heizer, Stéger, Fábri etc. We called this people sváb (schwabish, i think). They had protestant religion mainly, they even had their own cemetery.
As i know, they
1. moved abroad (mainly Germany, in 1956, and after the fall of the iron courtain)
2. Moved to bigger hungarian cities (a few of them)
3. Most of these families chosen spouse of their own kind, although, they were equal part of the community.
4. The ones, who stayed, doesn't learn german, cause they have nobody to speak to anymore, although, there is a vast population of German people, from Germany, who bought houses in the area (15-20 families in my village). Once i asked them, whether they understand what Schwäbisch people told them, but they didn't, they said, it's a wrung-out version of german. They were from Bayern, Altötting.
I knew an old couple (Imre Loósz (Emerich Loósz) and Magdolna Stéger (Magdalena Stéger)), who lived in our street, me and my parents helped them, when they got old, as they always helped us too earlier. They are gone now, but they have a wonderful story of ethernal love, hard work, and honest life, everyone should hear about...
Sometimes i have kind of a home sickness, missing my earlier home, just as it was, with these people, including the mentioned Schwäbisch families.