In my opinion, language is a tool which carries forward the cultural values across generations. If Language is given less importance, ultimately the cultural values diminish over time.
I basically hail from South India, and my mother tongue is Tamil. I went abroad to pursue my university education. It was sad to note that many friends of mine who where originally speakers of Tamil, couldn't converse well in Tamil just because their parents insisted from the early age to use English at all levels(even at home). Also they patronized the West more, by means of watching American Sitcoms, shows, movies etc. I could see them losing their cultural identity over time.
On the "Hathaway" side of the family, I am a 12th generation American -- eligible for membership in the Mayflower Society -- fortunately, I'm not much of a joiner.
On the "Vaughn" side of the family, I am only a 3rd generation American. "Vaughn" came from my paternal grandmother's maiden name, which was Von Gruenigen, sometimes spelled in the US without the space. Her father was from Bern, Switzerland. Her mother was from Hamburg, Germany. Both German and English were spoken in the home. Because my mother died when I was quite young, I grew up in my grand mother's home. While I learned enough German from her that I can read it somewhat, I didn't learn to converse in the language. I wish that I had. My father didn't either.
I think it is a mistake for an immigrant family to abandon their native language completely upon moving to a country where another language is predominant. While it is certainly important to learn the language of their new country, the maintenance of the native language aids the preservation of a family's culture.
I have attempted with varying degrees of success to inculcate in my children an appreciation for where we came from. The Hathaway name can be traced to the Doomsday Book in England. My wife's maiden name can be traced to the potato famine immigrations to America. My paternal grandmother's mother was an indentured servant when she came to America (She was only five; but her entire family was indentured. Her parents did not survive the journey and so she and her surviving sister were farmed out to two different sponsoring families. My great-grandmother's "sponsor" adopted her. Her sister's "sponsor" did not.) I inherited my grandmother's cook book. It has a number of recipes in it that can be traced to the Hebrock family from Hamburg from more than 150 years ago. I have my grandmother's German catechism and hymnal from the 1890s. Therefore, some of our cultural heritage has been preserved. BTW, I don't trumpet the roots of the Von Gruenigens very much. They were closely related to Fredrich Willhelm at whose feet many lay the blame for World War I.)
Excuse the rambling thoughts.