Should you localize your app upon launch?
If it is affordable for you and you know multiple languages, then definitely go for it. If not, this is not an investment that I would advise that you make early on. The things which you should primarily focus on are ASO, paid acquisition, finding acquisition channels which will lead to growth, finding your ideal users…these things are those which you should invest marketing dollars on.
I had a friend who localized his app for multiple markets and it was such a hard endeavor. He had multiple apps in his portfolio which were all performing so he thought the next step would be to localize it to other languages. He spent thousands of dollars on it but it did nothing to his downloads nor growth. This was a guy who had experience in ASO and ranks really well in the US but it did not move any needle. In contrast to this, I also had other friends with success stories so my point is that, the results are mixed and are unsure.
Having said this, go for it if it doesn’t cost you much but otherwise, re-target your focus and your marketing dollars to other aspects. If you still want to pursue localization despite this, check out websites where you can get affordable translation services such as Gengo.