/tell (insert name) Thank You! Even possible in this game?

[Tayce]

For pc it's /w [name]
Or just /r to to reply to a whisper/tell.

[Iceberg]

They should give us the option to keybind chat commands. I would bind R to /r.

[EdgeTW]

/t HANDLE text

Handle is not their character name, but the global tag they have for all their characters. You can turn on the option to see this above their head in the options menu.

/w, /t, /whisper, /tell all work to start a private conversation.