At the time of writing, speaking has 21 questions, and spoken-language has 17 questions. Looking through those questions, I can't seem to tell why one would choose one of the tags over the other (besides typing "speak" versus "spoke" into the tag-selection box). The tag wikis don't seem to help me disambiguate these, either.
Should there be a difference between these two tags (and if so, what?), or should one be synonymized to the other?