1. English is taught widely, and they need it anyway.
2. The lexicon to master is pretty short.
3. Kids naturally learn words. Say, with moderate interest in K-pop a European teen can remember Korean names, sometimes even in Korean script.
4. "For" in programming is not the same word as "for" in natural language. You may be under illusion that when it's in a local language, it will be easier to digest, but it's not. You need to explain its separate meaning anyway. And when you did it not in Programming English - sorry, you simply missed the opportunity. You spent roughly the same amount of time to create a redundant word-slot in student's memory.
5. "Tried" is not a valid metrics for success here. One could as well offer free cookies, and number of tries would be growing. But that elephant in the room will look at us without approval!