IPA: /ˈtʃætiər/
KK: /ˈtʃætiər/
More talkative or inclined to engage in conversation than someone or something else.
She became chattier after having a few cups of coffee.
Comparative: chattier
Superlative: chattiest
Chattier → It is formed from "chat" (from Old French *chater*, meaning to talk or chatter) and "-ier" (a suffix used to form adjectives indicating a tendency or quality). The word "chattier" means more inclined to talk or chatter than someone else.
Think of someone who is more inclined to 'talk' ('chat') — that's why 'chattier' means someone who talks more.