1) The "One Parent One Language" method
Without a doubt the most popular method of fostering bilingualism in a multicultural household is "One Parent One Language," otherwise known as OPOL. OPOL involves each parent speaking their own native language to their children, not mixing languages, period.
This method is deceptively simple. After all, all you have to do is speak your own language, right? What could be more natural! OPOL usually works quite well until the child starts school, at which point many parents often find that the language input from the minority language parent (that is, the parent whose language is not spoken in the country where the family lives) is simply not enough to overcome the overwhelming influence of the home country's language. Especially if the minority language parent is capable of speaking the majority language, a child will often "rebel" against the second language, preferring instead to speak the language that his peer group is speaking. Since most children do not like being labelled as different, they may find that speaking a second language sets them apart. One father, raising his child in China to be bilingual in Chinese and English noted that his daughter understood everything he said to her in English, but would stubbornly respond in Chinese.
OPOL becomes more complicated when the language of the host country is the common language between the two parents. Many parents raising their children bilingually in the United States have found it difficult to speak English with their spouse and a foreign language with their children. Multicultural families who speak Chinese at home in China may encounter similar problems. The children realise from the beginning that speaking English only is a viable option, and once they are old enough to make the choice, they may simply choose the language of the majority.
This doesn't mean OPOL is a bad option, but compared to other methods it requires almost all of the "work" to be done by one parent. As one mother said, "I got tired of always being the one who had to push English all the time. No one else was responsible for their English education, it was all on me. It was a lot of stress."