How did slaves learn to speak English?

Answer 1

In English speaking countries they learned enough English to get by - enough to know what they were being told to do. In many cases the slaves were of various tribal origins and could not speak to each other. A patois of English and other words would grow up

Answer 2

Slaves in the United States learned to speak English through various means, including interactions with slave owners, overseers, and other slaves. Many learned by listening and observing, as well as through informal education from other slaves or by attending secret gatherings where they could practice English. Over time, English became the dominant language among African slaves due to the need to communicate with their owners and among themselves.