Why does this script not work when detecting the player's jumps?

So I'm making a script that Everytime you jump, your speed increases overtime until it falls.

Problem is, it's not detecting anything or changing the speed.

char=script.Parent
humanoid=char:FindFirstChildWhichIsA("Humanoid")
falling=false

humanoid.StateChanged:Connect(function(oldState, newState)
	if newState == Enum.HumanoidStateType.Jumping then
		if falling==false then
			falling=true
			repeat 
				humanoid.WalkSpeed=humanoid.WalkSpeed+0.05
				wait()
			until falling==false
		end
	elseif newState == Enum.HumanoidStateType.Landed then
		if falling==true then
			falling=false
			humanoid.WalkSpeed=18
		end
	end
end)