articulate has 13 distinct synonyms spread across 5 of its 7 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is inarticulate.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
put into words or an expression
“He formulated his concerns to the board of trustees”
unite by forming a joint or joints
“the ankle bone articulates with the leg bones to form the ankle bones”
expressing yourself easily or characterized by clear expressive language
“articulate speech”
consisting of segments held together by joints
Synonyms, antonyms and the broader and narrower relations for articulate come from Princeton University’s WordNet. Full sources and licences.