The older a person is, the more difficult it is to acquire a new language, so I guess you could say that the younger you may be, the easier it will be to master multiple languages. Having said that, if a person of any age is confronted with total immersion in a new language or culture, it is safe to say that eventually, most people will become somewhat literate in the new or second language. The earlier the better. Make language learning fun and start as soon as you like. I have found that many children also do well learning a new language in the context of music and rhythm.
Several tapes are available commercially that sing songs in various languages.
Do not worry that the child will be confused if more than one language is spoken at home. Youngsters switch back and forth well, according to the setting and the dominant language spoken there. If he feels threatened he hits and kicks. It has been the teachers he kicks but he hit students yesterday. My husband picked him up from school because we told him the next time he acts like that we will come and get him.