My two and a half year old child goes to a Hebrew speaking maon, and we speak English at home. This worked for his older sister, as she is in first grade, and speaks both languages fluently. However our second child appears more relaxed and speaks more in Hebrew and not speaking English very much at home. We see him struggle to find words in English, and become frustrated. He will use gestures and make faces to get his point across. I did some reading and found:
A quote from a 2006 report at the Center for Applied Linguistics:
"Although many parents believe that bilingualism results in language delay, research suggests that monolingual and bilingual children meet major language developmental milestones at similar times."
It continues to say that despite the ongoing research on childhood bilingualism and researchers around the world doing their best to get the word out, the belief that language delay is a byproduct of bilingualism is still an ongoing misconception. Research shows that bilingual children start speaking within the same time frames as monolingual children. Some children start speaking before we expect it to happen and others much later, regardless of the number of languages spoken in the home.
I found two other points of research:
One Person, One Language (OPOL) is the most common family language system in use. For instance, Kees speaks his native Dutch, while his wife speaks English. Each parent or caregiver consistently speaks only one language to the child. Sometimes OPOL requires extra "language supplements," such as playgroups, visits from family, a trip to the country, or a native speaking nanny or au-pair. It helps tremendously for your child to hear that his parent isn't the only one who speaks this language. Kids are savvy little creatures who are quite capable of reasoning that they don't really need to know a language if it is only spoken by one other person.
A second option, slightly less common but tremendously successful is Minority Language at Home (ML@H). It simply means that everyone speaks the minority language at home, even if this language is not the native language of both parents. It is probably the most reliable method for raising truly native speaking children since it ensures consistent interaction from birth until the child leaves home. However, the ML@H parent has to be able to quell doubts and stay the course unwaveringly. When your child isn't speaking the community language on the same level as his or her monolingual peers (generally the ML@H child doesn't reach parity with them until around 5 years of age), it's difficult not to worry. Even when you know that your child is going to catch up, it can be daunting to watch him struggle. Some parents fear that he will never learn the primary language, even though this really only occurs when children are isolated from the primary language within a minority speaking community.