Have an enormous list of languages. Display the top n. Then have an option for bringing up the full list if your language isn't displayed in the top n. Have the top n determined dynamically by the n languages that have the most users already.
Advantages: Doesn't really matter what your main seed languages are, as they'll be overwritten by actual use. Can accommodate and acknowledge a sudden influx of people keeping journals in, eg, Navajo without any administrative insight needed. Is simple to use for most users, and actually possible to use for everyone.
Disadvantages: Extra DB load to determine what the top n languages actually are. (Which I don't think would amount to much, but IANA DB engineer). You'd have to make sure that the enormous list of languages was pretty damn comprehensive, which could be difficult.
no subject
Advantages:
Doesn't really matter what your main seed languages are, as they'll be overwritten by actual use.
Can accommodate and acknowledge a sudden influx of people keeping journals in, eg, Navajo without any administrative insight needed.
Is simple to use for most users, and actually possible to use for everyone.
Disadvantages:
Extra DB load to determine what the top n languages actually are. (Which I don't think would amount to much, but IANA DB engineer).
You'd have to make sure that the enormous list of languages was pretty damn comprehensive, which could be difficult.