IPA: /ˌɪn.ɑːrˈtɪk.jə.lə.si/
KK: /ɪnˈɑːrtɪkjuləsi/
The quality of being unable to express oneself clearly or effectively in speech.
His inarticulacy made it difficult for him to convey his thoughts during the presentation.
Inarticulacy → It is formed from "in-" (meaning not) and "articulare" (from Latin, meaning to articulate or express clearly) and the suffix "-cy" (meaning the state or condition of). The word "inarticulacy" refers to the state of being unable to express oneself clearly or effectively.
Think of 'not' ('in-') being able to 'express clearly' ('articulare') — that's why inarticulacy means the inability to articulate thoughts.