French Language, French
noun
I bet you can guess that フランス means "France." So what happens when you add language to it? You get the "France Language" aka the French Language.
ふらんすご, フランスご
The reading is just the on'yomi reading for 語 which is the reading you learned with the kanji. This is probably because it gets added onto a lot of other words so it's treated like a jukugo. For example: 日本語 = "Japanese Language." 中国語 = "Chinese Language." スペイン語 = "Spanish Language."
フランス語を学ぶために大学に行きました。
I went to college to learn French.
フランス語が上手なので、てっきりフランス人かと思ってました。
Your French is great and I thought you were a French person.
日本には、フランス語の本はあまりありません。
There are not many French books in Japan.