Considered + object used when the subject should be just another name for something. There are no rules in english about the number of letters required to comprise a word. Is considered as is an alternative way of saying the same thing.
Middle East Map Labeled
The words as or to be , when used after the word considered are nearly always. Actually, the way in which movies are classified based on language is a very good barometer of what is generally considered to be. I don't see any problem with your example about french as a language of.
The letter i, when capitalised, is considered a word.
Literally, that the object is the subject. Both considered to be and considered as are incorrect.
