We can support the obvious, simply by numbers...Most Widely Spoken Languages in the WorldLanguage ~ Approx. number of speakers1. Chinese 1,197,000,0002. Spanish 414,000,0003. English 335,000,0004. Hindi 260,000,000...but for my apps, I'm doing Chinese (both T & S) and the 'gateway' languages English, Spanish and French, at a minimum.A “gateway language” is a language of wider communication through which second-language speakers of that language can gain access to content and translate it into their own language. For devs, this means not having to go nuts supporting tons of languages, otherwise.I then track sales and add others based on activity in various locales and feedback/requests from users.As for Apple's stats, I've only seen hardware sales, and we all know how many languages they support. Stats for app sales would seem to vary depending on the type of app being tracked as well - what categories do you publish in now?