i've seen that some apps use this web https://crowdin.com/ to let the users help to translate on many languages.

I would really like to help translate the app to spanish

The people that speak a language, like spanish for example, translate a paragraph or a word of the app/web to spanish. Then the people that speak spanish vote if the translation is right and if it wrong they can correct it. And then the moderator approve the transaltion that think is right or maybe the one who have more votes.

I think it would really help to get to more languages faster, because when an user enter, he/she can choose what language he/she speak to help translate the app/web :)

So then everyone who likes the app could help to translate
Image example: https://metactrl.com/docs/crowdin-screenshot.png