Difficulty With Studying Foreign Languages.

I study English myself by self-educating.

I want to smoothly read English literatures that are about philosophy written in the old days, but in the present state of affairs it is impossible for me.
I could never do such a thing!!
I have a long long way to go.
When I use English , I am anxious about my use .
A popular proverb says that "Custom makes all things easy", but I don't think that it is easy to study a foreign language.
Every language connects with our thought profoundly, and it is not without saying that the langage that we use is effected by our own culture.
When I use English , I usually prepare with the English-Japanese dictionary.
If I don't know some English words that I want to use then the dictionary will help me of course, however, I am frequently worried about the following.
" What words should I select ?"
An example is when I want to translate " noberu"(noberu is Japanese. I use this word when I say something. )
If I look up noberu in the dictionary, I come across a lot of words about noberu!
For example, state,express,mention,observe.give, say,speak .
I can't understant which one I should select .
They all look the same to me and I thougt I was in trouble.
I think writing is easier than speaking because If I speak English I can't examine words and I have to think about  expressions that I already knew only by memory!