Checklist is quite a successful app. We have a rapidly growing user base and now that we have launched a new iOS app in addition to our Android app, we have the time to look at further expanding our marketshare. We already have about 6, mostly European languages, into which we have translated the app. So we started looking at additional languages and came up with the list above. Being based in the Netherlands, Europe, we can clearly see that we have missed the big picture: most of the world does not necessarily speak the languages we already had translated our app into. Or did we?
Your potential market is not necessarily based on the number of people in which country. One crucial factor is how many of them use apps and are internet literate. For us another factor is how "organized" of a society is the country made of. The Germans are well known for being organized and indeed we can see great growth there.
The list we came up with is a great guideline and a starting point for your own marketing efforts. Don't stick to it as is. Customize it to your own app potential market.