How can I hear a song and translate them
Be careful. I have used both babelfish.com and translate.com and both do have big flaws in translation. I got some gibberish I had to fix the sentences so they really go with the translation. In other words these sites only work for loose translation.
Get the lyrics to the song Then use this: http://babelfish.yahoo.com/ Spanish to English.
go on to translate.com upload the song and it should work.
