advantages and disadvantages of speaking more than two languages

Advantages of speaking more than two languages.

I'm learning English now in international school. It's because of my father's work so I came to Japan, but if I speak English well, there's many advantages for it. For example, it's easier to go university than people who speak just one language. And also easier to get a job. Also English is useful because many people in the world can speak English, so I need English when I go any other countries. And learning new language make people more smart and cool. For me, I'm studying English for university, but after that I'm going to learn maybe Japanese or something. 
English is useful because I'm living in Japan and I can't read Japaneses but mostly there's English announcement everywhere, so I never lost my way even I can't speak Japanese. But I'm going to learn Japanese soon. 


Difficulties or disadvantages of speaking more than two languages

The main thing is it takes long time to learn language. And we need a lot of money for it like our school.
Also it's difficult and sometimes stressful to learn it. I started learning English when I was grade 3. It's 5 years but it's still hard. Because of the pronunciation and word order in the sentence is so different to Korean. 
Also in our school, there's a lot of Japanese students. It makes me more difficult. Learning new language is good but it is tired.


If I were parent

English is we have to learn that because it's main important subject in Korea. If my son or daughter wants to learn it more deeply, it's good for them I think. But other language, I need to think of it. It's not good for main study like Korean and English. I think other than English is not important in school for Korean. If they learn more than three languages, I think it will make them worse than study hard for main subject.
So my opinion is for student, main subject is the most important.