Modifying crouch script using Slerp

Hello, i've found a crouch script on the web that makes the player as it says crouch. It changes the character controller to adjust the crouch height and what not. But one thing that i get really annoyed at is that the player instantly crouches down, instead i would like so it takes some time for the player to crouch down. Im thinking that Slerp is the right method to use, but i need help because i dont really understand Slerp. How would you adjust the script?

Thanks (:

 #pragma strict
 
 private var crouchHeight : float;
 
 private var standardHeight : float;
 
 private var crouching : boolean = false;
 
 private var controller : CharacterController;
 
 private var mainCamera : GameObject;
 
 function Start ()
 {
 
 controller = GetComponent(CharacterController);
 
 mainCamera = gameObject.FindWithTag("MainCamera");
 
 standardHeight = controller.height;
 
 crouchHeight = controller.height/4;
 
 crouching = false;
 
 }
 
 function Update () {
 
 if (Input.GetKeyDown(KeyCode.LeftControl))
 {
 
 if(crouching)
 {
 
 controller.height = standardHeight ;
 
 controller.center = Vector3 (0, 0, 0);
 
 mainCamera.transform.localPosition.y += crouchHeight;
 
 crouching = false;
 
 return;
 
 }
 
 if(!crouching)
 
 crouch();
 
 }
 
 }
 
 function crouch() {
 
 controller.height = crouchHeight;
 
 controller.center = Vector3 (0, -0.5, 0);
 
 mainCamera.transform.localPosition.y -= crouchHeight;
 
 crouching = true;
 
 }