〜ちゃん (chan)

Related patterns3

〜様さま
ちゃん is the intimate end, 様さま the ceremonial end of the same address scale.
〜くん
くん skews toward boys and junior men and can sound neutral in a workplace, while ちゃん skews toward girls, small children and pets and stays casual in every context.
〜さん
さん keeps a polite distance from any adult, while ちゃん shrinks that distance to children, pets and close friends, and sounds condescending aimed at a stranger.

attaches to a child's, a close friend's, or a pet's name affectionately

そこで何なにしてるの、ゆきちゃん？

soko de nani shiteru no, yuki-chan?

What are you doing over there, Yuki? casual

うちの猫ねこはタマちゃんという名前なまえです。

uchi no neko wa tama-chan to iu namae desu.

Our cat's name is Tama. neutral

Applying ちゃん to an adult stranger or a superior reads as babying them —
the target has to already be a child, an intimate, or a pet.