the reason why I study english is because I want to communicate with people from all of the world.I asked a native american "where is a restroom?（English）" in shopping center when I went to Hawaii before.and He said "ミギ ツギ ヒダリ（Japanese）".I was shocked.that's why I'm studying english. bu doğru görünüyor mu?

The reason why I study English is because I want to communicate with people from all over the world. I asked a native American* "where is the restroom?" in English in a shopping center when I went to Hawaii before, and he said "ミギ ツギ ヒダリ", in Japanese. I was shocked. That's why I'm studying English.

*when you say "native American", do you mean someone who was born and raised in America, or do you specifically mean someone whose race and ethnicity is Native American? If you mean someone who was just born/raised there, then you should say "an American native" to avoid confusion. If you mean someone whose ethnicity is Native American, then you need to capitalise both words.