I'd suggest "Immigrant Voices: New Lifes in America 1773-1986" edited by Thomas Dublin. It's a compilation of first hand accounts of immigrant experience in America over the centuries. Some people strived to become Americanized while others fought to retain their own culture while starting a new life in America. It could be helpful for your research. (This book is available on Allegro. I also have other books which discuss immigrant experience in America, Native-born views of immigrants, the lives of immigrants in America, etc.)
Best of luck :)