How do I make a tool that makes you say dialog?

So we can do that using this function from the service Chat https://developer.roblox.com/en-us/api-reference/function/Chat/Chat

So, first thing is it parameters:

partOrCharacter: has to be an instance, its the part that the message should appear above

message: Has to be a string, its the message.

color: This is the color the message will have, use this for reference when setting https://developer.roblox.com/en-us/api-reference/enum/ChatColor

EXAMPLES

This is going to display a BubbleChat above the player head.

--// Services
local Players = game:GetService("Players") 
local ChatService = game:GetService("Chat")

--// Constants
local Player = Players.LocalPlayer
local Character = Player.Character or Player.CharacterAdded:Wait()

ChatService:Chat(Character.Head, "Message", Enum.ChatColor.Green)