can someone pls help me with my walkspeed for a slider script?

im trying to make a script for my friend i have this so far but when he loads the script then it doesnt let him move and if you take out the G_ then you cant change your speed down

here is the script

spawn(function() while true do wait() game:GetService("Players").LocalPlayer.Character.Humanoid.WalkSpeed = (.G_value) end end)