Hmm, the B shortcut works fine for me also in Spanish, but indeed the G shortcut doesn’t. This happened because the G shortcut appears to be used by both the Wang Brush and the Eraser in Spanish.
Since we don’t actually document different shortcuts for different languages, and to avoid such problems, I think it would be better to stick to a single set of shortcuts for all languages. So I’ve fixed this by using the same shortcuts as in English for these tools, which is G for the Wang Brush and E for the Eraser (even though it’s called “Goma” in Spanish):