The three categories are related but assessed at distinct levels. One successful sentence does not conclusively establish the speaker's stable faculty, and an eloquent speaker may still utter a particular sentence with a flaw.
CategoryWhat is examined?
Eloquent wordIts sound, morphology, and intelligibility
Eloquent utteranceSyntax, fluency, and clarity of the complete expression
Eloquent speakerThe established ability to produce such speech
A particular Arabic sentence can be evaluated as an utterance; reliably producing clear sentences in varied contexts concerns the speaker's acquired faculty.