I have contact with English on the Internet in my room on Sunday.
I like the foreign musics. Sometimes I access my favorite artist's web site.
On the web, all things (biography, lyrics, faq,etc) are written in English, of course.
So, I willy-nilly have to contact with English if I'd like to see those things.
Although the lyrics of the songs are written in English,
they are often hard to grasp.
Therefore, I listen to the music not to undestand the lyrics
but to get used to English, and how to speak and pronounce it.
That is impossible only when listening to the Japanese ones, I think.