IPA: /ɪnˈɑːtɪkjʊlətli/
KK: /ɪnˈɑːrtɪkjʊlətli/
In a way that is not clear or effective in expressing thoughts or ideas.
He spoke inarticulately, making it hard for others to understand his point.
Inarticulately → It is formed from "in-" (meaning not), "articulare" (from Latin, meaning to articulate or express clearly), and "-ly" (meaning in a manner). The word describes the manner of speaking that is not clear or coherent.
Think of 'not' ('in-') being able to 'express clearly' ('articulare') — that's why inarticulately means speaking in a way that is unclear.