What hooks me most about a narrator's voice is how alive it feels—like sitting next to a person who has their own rhythm, opinions, and
scars. Diction is the obvious lever: the specific words a voice picks (short, clipped verbs versus lush adjectives) immediately set mood and authority. But it's the little punctuation choices, sentence length, and the habit of repeating certain metaphors that make a voice feel human. When I read '
The Catcher in the Rye', the conversational stumbles and colloquialisms are what made Holden's voice impossible to forget.
Pacing and syntactic variety are huge too. A string of long, winding sentences creates a dreamlike, meandering narrator; short, staccato lines feel urgent or brittle. Point of view — first person's intimacy, free indirect style's slipperiness, third-person limited’s cozy
distance — determines what the reader knows and how close they feel. I also love when authors lean into sensory specificity: a narrator who notices a habit like rubbing a scar or naming the exact smell of burnt coffee becomes trustworthy, or deliciously unreliable.
Finally, consistency with intentional deviations is gold. Keep a register that fits the character, but break it sometimes to reveal emotion or trauma. In my own reading, those jolts are the moments I feel most connected to the voice.