In Chang-rae Lee's Native Speaker, Henry Park, the son of Korean immigrants, experiences many difficulties with assimilation and alienation throughout his life, and he struggles to fit in both in American culture and in Korean culture. Let's look at some examples of Henry's struggles.
When Henry starts school, he does not speak English very well. His parents speak Korean at home, and that is Henry's first language as well, even though Henry was born in America. The other children tease him about his struggles and call him "Marble Mouth," and Henry has his first experience of not fitting in.
As the years go by, Henry learns to speak clearly and does well in school, yet he has some emotional issues that stem from his Korean heritage. Henry has difficulties connecting with other people and showing his emotions. On one hand, Henry thinks that his father is old-fashioned and too attached to the standards of Korean life and culture. But on the other hand, Henry himself follows those standards, at least to a point. Henry withdraws from emotional situations, for instance. His wife, Leila, struggles with this, especially after their son dies. Henry cannot express his grief or comfort her. He is caught between his Korean heritage and the American expectations of his wife, and he does not perfectly fit into either.
Finally, we can look at Henry's work. He is employed by a company that essentially spies on immigrants and ethnic neighborhoods to keep tabs on radicals and labor organizers. Henry fits into the Korean neighborhood as the son of immigrants, but he is, at least in some ways, betraying his own heritage by his activities. He is, once again, pulled in two different directions.