Soft-spoken and Smooth-spoken

Soft-spoken adjective - Having a speaking manner that is not loud or harsh.

Smooth-spoken and soft-spoken are semantically related. In some cases you can use "Smooth-spoken" instead an adjective phrase "Soft-spoken".

Smooth-spoken adjective - Expressing yourself readily, clearly, effectively.

Soft-spoken and smooth-spoken are semantically related. Sometimes you can replace phrase "Soft-spoken" with "Smooth-spoken", this phrases are similar.