To my mind, no articles are necessary in your sentence.
\"a language\" may refer to an existing language, e.g. Polish is a Slavonic language
Thus, \"an offensive language\" would refer to a special kind of language and would include more than words.
\"offensive words\" = \"offensive language\". You wouldn\'t put an article before the phrase with \"words\", right?
As to \"(an) excessive use\", I think I\'ve heard both, but I would prefer to omit the article in this phrase too.
> book, house - no problem
OK, buy me a book, or a house, will you please, Cebulka :-)