Cage,

Just a few things to help you out with here. When you use "want" or "want to be able" you just need to add the infinitve of the things you "want to be able to do". I corrected your post to do that.

Be careful of articles, "the" and "a" and plurals. I know that Japanese does not have these so it can be tough but keep working at it.

"Others' opinion" is written better as the opinions of others. Both are plural as there are "many" others and many "opinions".

I underlined some phrases that are understandable in English but could be improved:

"My English isn't good enough yet and my goal, to get proper, natural speaking skill is still far."

could be written better as:

"I have a long way to go before I can speak English in a natural way" OR:

"I have a long way to go before I can speak English fluently" OR

"I have yet to achieve my goal of speaking English naturally".

Each of these have slightly different meanings, depending on your actual goal with English. You do not need to state that "My English isn't good enough yet" as that is implied by the second half of the phrase... what your goal is. When describing goals  "a long way off" or "I have yet to achieve" are good phrases to use.

"I'm happy if you could help me, and on the other hand I'm very interested in teaching my mother tongue."

could be better written as:

"I would be happy if you could help me. I could also help you with Japanese, my native language".

"I would be happy" is the better form of the verb. "Also" should be used here as you mean "as well" or "in addition to". Use "on the other hand" for alternatives:

"We can go shopping. On the other hand we could go to the movies".

Regards,

Jas 

Please Correct My Sentences and Make Them More Natural. (sorry, reentry)

My English isn't good enough yet and my goal, to get proper, natural speaking skill is still far. I want to become be able to discuss on a wide range of topics, to understanding others' opinion the opinions of others and expression to express mine correctly. I'm happy if you could help me, and on the other hand I'm very interested in teaching my mother tongue.