What "derive" means in this context?

Question

This comes from the book "Black Rednecks And White Liberals" by Thomas Sowell

"Attempts to derive the black manner of speaking from slavery and its parallel among whites as an influence from black speech were answered by a Southern historian who asked, “from whence came the drawl of the people of the upper Great Plains and of the Blue Ridge, Smoky, and Cumberland Mountains, who have had little or no contact with the Negro?”"

I found this definition for "derive" 3. (tr) to trace the source or development of

Is this the correct definition? does "trace" in this definition mean: c. To locate or ascertain the origin of: traced the money to a foreign bank account.

What is confusing to me is that the sentence from the book says "derive from" So there were "attempts to derive the black manner of speaking from slavery" but the slavery itself is the source of black speech they were looking for.

Answer 1

Yes, trace is the correct definition of derive in this context.

What the sentence is trying to say is that they were trying to trace the source of the black speech to slavery, so yes, they were considering slavery to be the source of the black speech.