Second Class Citizen is a novel written by Buchi Emecheta. It was first published in 1974 and follows the story of Adah, who eventually leaves her homeland and moves to Great Britain, following her childhood dream of living there, hoping to lead a life free of the restrictions she would have faced back home in Nigeria.
In order to answer your question, it is important to point out that Adah does not move to Great Britain on her own. Instead, she follows Francis, her husband, who had moved there first. Francis and Adah got married before moving to England, and their first child is called Titi.
Titi was born in Nigeria and spent the first part of her childhood there. The move to England is quite difficult for Titi. You can see that in the fact that it leads to her behaviour changing. For example, you could explain that Titi was initially a happy, talkative child back home in Nigeria, but she stops being as open and talkative after having moved to England. This is totally understandable, given that life in England was very different to the life she had been used to in Nigeria. However, you might also want to point out that this is probably also caused, at least to some extent, by Titi's relationship with her very strict and dominant father. Living in England without her friends and family, being forced to converse in English rather than her native language, would have been very difficult for Titi.