I believe you guys have seen the movie Spanglish. Its a movie about a single mother and daughter who emigrate from Mexico to America in search for a better life. When they first arrived in America, you can see that Flor (mother), still stays within the Mexican community and is reluctant to step across the cultural divide. On the other hand, her daughter have already learned to speak English. Only when the money problem surfaced that she starts to work for a rich American family. You can see that even then, she have no knowledge of English and there were difficulties in communicating with the Claskys. After one particular incident, Flor then felt the need to learn English which she seek help from her daughter, Christina.
Christina was offered a scholarship in a Posh private school with the help of Deborah and we can see that Flor is not happy about it. I think that she was afraid that her own daughter will be influenced and become Americanised and forgot their own roots. She was worry about it and thinks one in two things will happen: (1) To be the odd one, or (2) Become one of "them". She was worried that Christina is afraid of being who she is. Towards the end of the movie, Flor asked Christina, "Is what you want for yourself to become someone very different than me?" It shows that how important it is to hold on to one's identity and Christina was able to realize it.
Flor's unwillingness to let Christina to fully assimilate into the American society because she was maintaining her ethnicity. In my opinion, I think that the feature of Ethnicity and staying loyal to their L1 can be seen here. Living in an completely foreign country, there are chances that there might be more of language shift than language maintenance. However based on this movie, its otherwise.
Now, what do you guys think?