Pluralizer improvements (multi languages)

I added a $language attribute in the Pluralizer's singular() and plural() function, because I needed to use it with the french grammar rules.

Unfortunately, the french language is tricky, and I was not really able to make all the rules for singularizing a word. For example, plural verbs ending in AUX can end in AL or in AU when singular.
I was pondering using a list of the singular words finishing in AL (a few hundreds) or maybe throwing an exception, when the plural() function is called with a word that ends with AUX.
What do you think ?

In my case, I only use plural() so it's okay.