Correção para Celso de Almeida Po: Growing up...

I wanna study ostensibly for to my English improve the long term.
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Avatar do usuário Redseahorse 8610 1 13 159
Sugestão:

I WANT OSTENSIBLY STUDY English FOR IMPROVING IT IN THE LONG TERM.
Avatar do usuário PPAULO 41415 6 32 727
I want to study English intensively, it´s my goal to get improving and improving, until I become proficient in the long term. Then I will communicate with others in that language confidently and effectively.

You could stop at the period after "long term", though.

To kis (keep it simple) and piggybacking on your sentence:
I want to study extensively to improve my communication skills/fluency/proficiency in the long term.

And there are other ways to express that...of course!