Changing the game's language

I had a quick look using the search function but couldn't find an answer to this. I'm trying to change the language from English to French to lightly brush up on my language skills while playing the game but English is the only option available in the preferences. I'm presuming I chose to only install that language in the setup, is there any way to install new language files without having to reinstall the whole game again? As in, are the files available to download from somewhere?

I dont think you can change the selected language after the game has started so you will have to start again. Most of the language files are avaialable with the demo