IPA: /ˌɪn.kəʊˈhɪə.rənt.li/
KK: /ɪnˈkoʊhɪrəntli/
In a way that is not clear or logical, making it difficult to understand.
He spoke incoherently after the accident, making it hard to follow what he was saying.
Incoherently → It is formed from "in-" (meaning not) and "coherent" (from Latin "cohaerentem", meaning sticking together or logically connected) and the suffix "-ly" (meaning in a manner). The word "incoherently" means in a manner that is not logically connected or does not stick together.
Think of 'not' ('in-') being combined with 'sticking together' ('coherent') — that's why incoherently means something that doesn't make sense or is not logically connected.