Map of Language Distribution in Europe
i258.photobucket.com
i258.photobucket.com
It seems that where more than one language share one territory, the area is colored with the language that is more 'traditional' or specific to it, even if other ('invading') languages have demographic majority nowadays.
With that criteria, they could have expanded the area for Franco-Provençal quite a bit. Also, I think Astur-Leonese would deserve its own color rather than being incorporated into the Castillian group.
http://en.wikipedia.org/wiki/Astur-Leonese_language
And just to nitpick, since the map notices small pockets in some zones:
- there are pockets of speakers of Galizan-Portuguese languages in Extremadura,
- there is this small region that Spain conquered in 1801 from Portugal, which still speaks Portuguese:
http://en.wikipedia.org/wiki/Olivenza
- and there is a small pocket of speakers of the Catalan family of languages in Corsica.
A more officialist take on the current situation is:
http://en.wikipedia.org/wiki/European_languages
This is more realistic in assessing majorities and more politically orthodox, but not any more correct IMO. Ignoring minoritary languages altogether is no less of a lie than presenting them as if they were predominant. The map sticks to political frontiers rather than language areas. Also, I don't know why it doesn't recognize Asturianu, a language co-official with Castillian, while it does recognize Basque, which is minoritary and co-official too.
In that map we see that the Building Nation efforts in France and Great Britain have been more 'successful' than in Spain. So, while it's common in colloquial settings to use the name "Spanish" to refer to Castillian (even the academy of the language calls it "Lengua Española"), it's an aberration in a technical document. It would make more sense to call English Unitedkingdomish.
I was serious when I asked if this map was from 1750. It looks about right for that, at least for the western European countries whose history I know well. (I can only guess about all the ethnic pockets in Russia).
My guess is the author is assuming that everyone knows where the dominant, 'imperial' languages (English, French, German, Spanish, Russian ...) are spoken, and aims to represent the deltas from those. Either that, or it has an exaggerated anti-imperialist bias.