articulate(v.)
1590s, “to divide speech into distinct parts”, from Latin articulatus, past participle of articulare “to separate into joints,” also “to utter distinctly,” from articulus “a part, a member, a joint”.
The generalized sense of “express in words” is from 1690s. In a physical sense, “to join, to attach by joints,” it is attested from 1610s. The earlier meaning “set forth in articles” (1560s) now is obsolete or nearly so.
Related: Articulated; articulating.