It is necessary to learn foreign languages. That's why pupils have got such subject as a foreign language at school. Everybody knows his own language, but it is useful to know foreign languages.
I learn English, because I understand that I can use it. For example, if I do to England I'll be able to speak English too. English is used not only in England, but also in other countries. I learn English because I want to read foreign literature in the original. I know and like such English and American writers as Charles Dickens, Mark Twain and others. I understand that I must learn English. If I know English well, I'll be able to go to the library and take books by English and American writers in the original.
I like to travel. But it is difficult to visit countries, when you don't know the language of these countries. If I know the language of the country, where I am going to, it will be easy do travel there. If I want to ask something, I can do it in English.
I like to read books. And I like to read newspapers, too. If I know, for example, English I'll be able to read English newspapers and magazines.
Knowledge of different countries to understand each other, to develop friendship among them. For example, we have a foreign exhibition in Moscow. If is easy for me to visit this exhibition.
You can see a lot of advertisement, signboard, names in the streets. They are in foreign languages. Very often they are in English. If you know English, you can read and understand them.
Now we buy many clothes from other countries. If you know English well, you can read something about the size of this or that thing. It is clear for you what it is made of.
There are a lot of films in foreign languages. If you know them, you can understand films without any help.
There are international friendship camps in the world. If you can speak foreign languages, it will be easy for you to visit such camps and speak with the boys, girls, men, women who do not know Russian.