> English is the lingua franca

Yes, so to learn English, ppl need some kind of "translator" tool, no?

The most comprehensive one (but very old) out there is stardict.

I cannot comment on how useful these tools are or not since I started using computers in English (there were no translations to my language back then) without any such tool or without knowing any English. I had the of speaking another Germanic language but I would say if you know some basic you can use computers without any tool assistance and learn English quickly.

No, you don't need a translator tool to learn other language. Certainly not one that automatically translates everything you copy.

Once you know the basics (which a translator won't teach you) the most effective way to become proficient is practice, which is the opposite of relying on a tool to translate things for you.