In the book the secret Latina why does chambers call herself a secret Latina

Chambers calls herself a "secret latina" because she is both black and latina, but she looks black so people can't understand that she can also be latina.

Her mother is from Panama, and she wants to celebrate that part of her culture, too, so she learns Spanish, visits Panama, explores the culture there and incorporates it into her life.

However, because she looks black (only) when she is home in New York, she is "secretly" latina because nobody else can understand the duplicity of being both black and latina.