How to you make a custom walkspeed system with FE?

I am trying to make a custom walkspeed system. Here's how it works: There's a textbox where you type in a number in. The textbox has a value inside it. The textbox text should be in that value. But when I type in the number I want my walkspeed to be, it changes it to zero. Any help?

Here's what I've tried:

local speed = script.Parent.Speed.SpeedValue
local textBox = speed.Parent
local player = game.Players.LocalPlayer
local playerGui = player.PlayerGui
local walkspeedGui = playerGui.Sprint

local function changeSpeed()
	local text = textBox.Text
	if text ~= nil then
		textBox.Text = speed.Value
		local humanoid = player.Character:FindFirstChild("Humanoid")
		if humanoid ~= nil then
			humanoid.WalkSpeed = speed.Value
		end
	end
end

textBox.FocusLost:Connect(function(enterPressed)
	changeSpeed()
end)