What would you think of a Spanish person assuming a white blonde blue eyed person speaks Spanish?

Well SPAIN was a Celtic nation before the invasions and they had a tendency to be rather light haired and skin as well as red and auburn hair colors with a variety of other eye colors as well...

N.Shadows 

I was waiting in a UE line in Tulare CA several years ago. The woman at the counter called out a number , and a blonde haired blue eyed white woman went up to the counter. Two Mexican ladies in line ahead of me complained in Spanish that the white people were always called first. Within a couple of minutes, that white lady came back to the 2 Mexican ladies and told them in Spanish that she couldn't speak English. She was from Argentina, then asked could 1of them please interpret for her at the interview. Those 2 Mexican ladies were embarrassed and apologetic for their assumption.

I know several who speak Portuguese.

No, because who doesn’t know how to speak at least a little Spanish? 😐🌺