Crouching with a specific Script

I know there are tons of different crouching scripts, but I can't seem to implement them into my script.. I will post my code! (: If y'all have any tips or points to make, that would be wonderful!

 using UnityEngine;
 using System.Collections;
 
 [RequireComponent (typeof (CharacterController))]
 public class FPSwalkerEnhanced: MonoBehaviour {
 
     public float walkSpeed = 6.0f;
 
     public float runSpeed = 11.0f;
 
     public float crouchSpeed = 3.0f;
 
     // If true, diagonal speed (when strafing + moving forward or back) can't exceed normal move speed; otherwise it's about 1.4 times faster
     public bool limitDiagonalSpeed = true;
 
     // If checked, the run key toggles between running and walking. Otherwise player runs if the key is held down and walks otherwise
     // There must be a button set up in the Input Manager called "Run"
     public bool toggleRun = false;
 
     public float jumpSpeed = 8.0f;
     public float gravity = 20.0f;
 
     // Units that player can fall before a falling damage function is run. To disable, type "infinity" in the inspector
     public float fallingDamageThreshold = 10.0f;
 
     // If the player ends up on a slope which is at least the Slope Limit as set on the character controller, then he will slide down
     public bool slideWhenOverSlopeLimit = false;
 
     // If checked and the player is on an object tagged "Slide", he will slide down it regardless of the slope limit
     public bool slideOnTaggedObjects = false;
 
     public float slideSpeed = 12.0f;
 
     // If checked, then the player can change direction while in the air
     public bool airControl = false;
 
     // Small amounts of this results in bumping when walking down slopes, but large amounts results in falling too fast
     public float antiBumpFactor = .75f;
 
     // Player must be grounded for at least this many physics frames before being able to jump again; set to 0 to allow bunny hopping
     public int antiBunnyHopFactor = 1;
 
     private Vector3 moveDirection = Vector3.zero;
     private bool grounded = false;
     private CharacterController controller;
     private Transform myTransform;
     private float speed;
     private RaycastHit hit;
     private float fallStartLevel;
     private bool falling;
     private float slideLimit;
     private float rayDistance;
     private Vector3 contactPoint;
     private bool playerControl = false;
     private int jumpTimer;
 
     private float height;
 
     void Start() {
         controller = GetComponent<CharacterController>();
         myTransform = transform;
         speed = walkSpeed;
         rayDistance = controller.height * .5f + controller.radius;
         slideLimit = controller.slopeLimit - .1f;
         jumpTimer = antiBunnyHopFactor;
                 height = controller.height;
     }
     
     void FixedUpdate() {
         float inputX = Input.GetAxis("Horizontal");
         float inputY = Input.GetAxis("Vertical");
         // If both horizontal and vertical are used simultaneously, limit speed (if allowed), so the total doesn't exceed normal move speed
         float inputModifyFactor = (inputX != 0.0f && inputY != 0.0f && limitDiagonalSpeed)? .7071f : 1.0f;
 
         if (grounded) {
             bool sliding = false;
             // See if surface immediately below should be slid down. We use this normally rather than a ControllerColliderHit point,
             // because that interferes with step climbing amongst other annoyances
             if (Physics.Raycast(myTransform.position, -Vector3.up, out hit, rayDistance)) {
                 if (Vector3.Angle(hit.normal, Vector3.up) > slideLimit)
                     sliding = true;
             }
             // However, just raycasting straight down from the center can fail when on steep slopes
             // So if the above raycast didn't catch anything, raycast down from the stored ControllerColliderHit point instead
             else {
                 Physics.Raycast(contactPoint + Vector3.up, -Vector3.up, out hit);
                 if (Vector3.Angle(hit.normal, Vector3.up) > slideLimit)
                     sliding = true;
             }
 
             // If we were falling, and we fell a vertical distance greater than the threshold, run a falling damage routine
             if (falling) {
                 falling = false;
                 if (myTransform.position.y < fallStartLevel - fallingDamageThreshold)
                     FallingDamageAlert (fallStartLevel - myTransform.position.y);
             }
 
             // If running isn't on a toggle, then use the appropriate speed depending on whether the run button is down
             if (!toggleRun)
                 speed = Input.GetButton("Run")? runSpeed : walkSpeed;
 
             // If sliding (and it's allowed), or if we're on an object tagged "Slide", get a vector pointing down the slope we're on
             if ( (sliding && slideWhenOverSlopeLimit) || (slideOnTaggedObjects && hit.collider.tag == "Slide") ) {
                 Vector3 hitNormal = hit.normal;
                 moveDirection = new Vector3(hitNormal.x, -hitNormal.y, hitNormal.z);
                 Vector3.OrthoNormalize (ref hitNormal, ref moveDirection);
                 moveDirection *= slideSpeed;
                 playerControl = false;
             }
             // Otherwise recalculate moveDirection directly from axes, adding a bit of -y to avoid bumping down inclines
             else {
                 moveDirection = new Vector3(inputX * inputModifyFactor, -antiBumpFactor, inputY * inputModifyFactor);
                 moveDirection = myTransform.TransformDirection(moveDirection) * speed;
                 playerControl = true;
             }
 
             // Jump! But only if the jump button has been released and player has been grounded for a given number of frames
             if (!Input.GetButton("Jump"))
                 jumpTimer++;
             else if (jumpTimer >= antiBunnyHopFactor) {
                 moveDirection.y = jumpSpeed;
                 jumpTimer = 0;
             }
         }
         else {
             // If we stepped over a cliff or something, set the height at which we started falling
             if (!falling) {
                 falling = true;
                 fallStartLevel = myTransform.position.y;
             }
 
             // If air control is allowed, check movement but don't touch the y component
             if (airControl && playerControl) {
                 moveDirection.x = inputX * speed * inputModifyFactor;
                 moveDirection.z = inputY * speed * inputModifyFactor;
                 moveDirection = myTransform.TransformDirection(moveDirection);
             }
         }
 
         // Apply gravity
         moveDirection.y -= gravity * Time.deltaTime;
 
         // Move the controller, and set grounded true or false depending on whether we're standing on something
         grounded = (controller.Move(moveDirection * Time.deltaTime) & CollisionFlags.Below) != 0;
     }
 
     void Update () {
         // If the run button is set to toggle, then switch between walk/run speed. (We use Update for this...
         // FixedUpdate is a poor place to use GetButtonDown, since it doesn't necessarily run every frame and can miss the event)
         if (toggleRun && grounded && Input.GetButtonDown("Run"))
             speed = (speed == walkSpeed? runSpeed : walkSpeed);
     }
 
     // Store point that we're in contact with for use in FixedUpdate if needed
     void OnControllerColliderHit (ControllerColliderHit hit) {
         contactPoint = hit.point;
     }
 
     // If falling damage occured, this is the place to do something about it. You can make the player
     // have hitpoints and remove some of them based on the distance fallen, add sound effects, etc.
     void FallingDamageAlert (float fallDistance) {
         print ("Ouch! Fell " + fallDistance + " units!");   
     }
 }

I believe I add a crouch speed and crouch height... But then the Lerp catches me off guard! (: