You look to be correct on your assessment in languages.
As far as foreign cards go, the value depends almost solely on the market they are sold or traded in.
Generally speaking, a non-English card is worth about 10% more, though this is affected by which language, what card etc. For instance, A lot of my friends and local players go crazy for Japanese or Korean cards, sometimes valuing them at close to double.
On the other hand, in places like Europe where so many languages are spoken so close to one another, alternate language cards don't usually fetch much more.
Bottom line: In the case of a very playable common like yours, those would probably go for an extra dollar over regular price here in New England.