One of the heated topics that arises once a couple from different cultural backgrounds (speaking different languages) decides to have a family is what language to raise their children speaking. In our case, we decided to go for the dual-language route, i.e., me speaking only in Greek to my daughter, and my husband who is Irish, only in English and occasionally in Irish (that really makes her trilingual!). And it works just fine. She is able to grasp everything we say to her, and what is more she can use both languages on different occasions. Often it can be very entertaining: living in an English speaking country gives me and my daughter the advantage of having our own little secret code-lingua franca nobody understands (or so we think). In addition, my husband has enriched his Greek vocabulary substantially, to the point where he impresses me with his progress.
Many theorists have expressed diverse opinions on the subject of bilingualism, yet all unanimously agree on one thing: the benefits of thinking and expressing oneself in more than one languages is rewarding, stimulating, priceless:
"Sometimes children from bilingual families tend to speak later. But experts say the delay is temporary, and the advantage of knowing two languages outweighs that small disadvantage. There's often a slight lag in the speech-language development of both languages in a bilingual household. Over time, though, bilingual children can catch up with their peers and have the benefit of communicating in two languages with proficiency," says Patti Hamaguchi, author of Childhood Speech, Language, and Listening Problems: What Every Parent Should Know. In other words, kids raised in a two-language household tend to start talking a bit later, but eventually they get on track. And in the long run, speaking two languages (or more) offers big benefits. In the job market, for example, fluency in more than one language can open many doors. It also creates opportunities for education, travel, communication with older relatives, and so on."
Source: Babycenter