The english language also has many french words in it wich came from the migration of the normands to the british isles. i think the different terms as british english, american english, are for the dialects spoken in each region. the language is called english, but dialects differ from one place to another. you should go to belgium, they have flemish, wich is the collection of dialects that come from dutch that they spoke. even 10kms away from the place you live in belgium people talk a completely different dialect. Although for technical purposes the language is refered as dutch. we have that as well everywhere in latin america, our language is spanish (except for brazil) but it varies in coloquial words from one country to another and within regions of the same country