As I'm sure we are all aware, racism is alive and well in the United States. The prevalence of racism, however, is not systematically maintained through blatant acts against people of color. It has been maintained past the Civil Rights Movements, through all the laws and court cases banning racist acts, by microaggressions.
Microaggressions are commonplace spoken and unspoken slights that convey derogatory messages to individuals based on their position in a marginalized group. Whether they are intentional or not, micro-aggressions serve to subjugate marginalized people, every day, in the most casual and systematic way, as well as keeping marginalized people as separated from mainstream white culture as possible.
Common microaggressions against people of color generally include comments on their race. "What are you?" is a common question asked by white people. This question dehumanizes the individual you are asking, as well as pigeon holes them so that you can decide how well to treat them as people. Asking people of color why they share attributes commonly associated with white culture such as, "Why do you sound white?" is meant to keep marginalized people out of the mainstream white culture.
Backhanded compliments such as "You're not like most... people" really means, "Why would you want to be like your own culture?" This comment attempts to alienate other cultures and places white culture on a pedestal. Also, "You're pretty for a... girl" does nearly the same thing. It says that people of color aren't attractive, and a white aesthetic should be striven for.
These are only a few examples, generally said by white people. In light of this, we as white people should attempt to remain conscious of what we say to our PoC friends. We have ingrained racism, and the best we can do to fight it is to always stay on alert for micro-aggressions that we might say, whether intentionally or not.