This is a question I've had forever, so thanks for posting it.
Re Gallego, I have a friend who grew up in Galicia, and learned from her that the language is mutually intelligible with Spanish, but more in the sense that if you speak Portuguese (which Gallego resembles closely--no surprise, since it borders Portugal) or Italian you can get the gist of it, and vice versa. Also, people in Galicia didn't have much choice to learn Spanish. Growing up under Franco she and her friends were not permitted to speak Gallego in school; if they did, they were punished. Tout ca change ...
Teaneck, New Jersey