Adds language selector to preferences

[bkmeneguello]

No description provided.

[vkbo]

Thanks!

The listLanguages function was missing a few checks, and assumed the wrong default language. It's British English, not American English. I rewrote it to a simpler syntax where I could add those checks.

Also, remember to add docstrings to functions and please don't use the hanging indentation scheme. It breaks indentation guides for those who use them in editors (I do) and is a lot harder to read.