NullRefenceException Using Arrays

Basically every line that contains a array throws me a nullrefenceexception even though the array is defined the inspector

 using UnityEngine;
 using System.Collections;
 
 public class PlayerMovement : Player {
         
     //Fields
     public float[] OriginalXYZtranslateSpeed;
     private float[] _currentXYZtranslateSpeed;
     public float[] MaxXYZtranslateSpeed;
     public float[] AccelerationXYZtranslateSpeed;
     public float[] DeaccelerationXYZtranslateSpeed;
     public float JumpHeight;
 
     // Use this for initialization
     void Start ()
     {
 
     }
     
     // Update is called once per frame
     void Update () 
     {
         transform.Translate(_currentXYZtranslateSpeed[0] * Time.deltaTime, _currentXYZtranslateSpeed[1] * Time.deltaTime, _currentXYZtranslateSpeed[2] * Time.deltaTime);
         KeyboardMovement();
     }
 
     void KeyboardMovement()
     {
         //Sideways movement
         if (Input.GetKey(KeyCode.A) && (_currentXYZtranslateSpeed[0] >= -MaxXYZtranslateSpeed[0]))
         {
             _currentXYZtranslateSpeed[0] -= AccelerationXYZtranslateSpeed[0];
         }
         else if (Input.GetKey(KeyCode.D) && (_currentXYZtranslateSpeed[0] <= MaxXYZtranslateSpeed[0]))
         {
             _currentXYZtranslateSpeed[0] += AccelerationXYZtranslateSpeed[0];
         }
         else if (_currentXYZtranslateSpeed[0] > OriginalXYZtranslateSpeed[0])
         {
             _currentXYZtranslateSpeed[0] -= DeaccelerationXYZtranslateSpeed[0];
         }
         else if (_currentXYZtranslateSpeed[0] < OriginalXYZtranslateSpeed[0])
         {
             _currentXYZtranslateSpeed[0] += DeaccelerationXYZtranslateSpeed[0];
         }
 
         //Forward and backwards movement
         if (Input.GetKey(KeyCode.W) && (_currentXYZtranslateSpeed[2] <= MaxXYZtranslateSpeed[2]))
         {
             _currentXYZtranslateSpeed[2] += AccelerationXYZtranslateSpeed[2];
         }
         else if (Input.GetKey(KeyCode.S) && (_currentXYZtranslateSpeed[2] >= -MaxXYZtranslateSpeed[2]))
         {
             _currentXYZtranslateSpeed[2] -= AccelerationXYZtranslateSpeed[2];
         }
         else if (_currentXYZtranslateSpeed[2] > OriginalXYZtranslateSpeed[2])
         {
             _currentXYZtranslateSpeed[2] -= DeaccelerationXYZtranslateSpeed[2];
         }
         else if (_currentXYZtranslateSpeed[2] < OriginalXYZtranslateSpeed[2])
         {
             _currentXYZtranslateSpeed[2] += DeaccelerationXYZtranslateSpeed[2];
         }
 
         //Jump
         if (Input.GetKey(KeyCode.Space) && IsGrounded())
         {
             rigidbody.velocity = new Vector3(0, JumpHeight, 0);
         }
     }
 }