My frog only goes straight, no matter what key you press WASD or arrows. Here is my code:

private Animator playerAnimator;
private float moveHorizontal;
private float moveVertical;
private Vector3 movement;

// Use this for initialization
void Start () {
    //Gather the Animator component from the Player GameObject
    playerAnimator = GetComponent<Animator> ();
}

// Update is called once per frame
void Update () {
    moveHorizontal = Input.GetAxisRaw("Horizontal");
    moveVertical = Input.GetAxisRaw("Vertical");

    movement = new Vector3(moveHorizontal, 0.0f, moveVertical);
}

void FixedUpdate() {

    //If the player's movement vector does not equal zero...
    if (movement != Vector3.zero)
    {
        // ... then play the player jump animation.
        playerAnimator.SetFloat("Speed", 3f);
    }
    else {
        // Otherwise, don't play the jump animation
        playerAnimator.SetFloat("Speed", 0f);
    }

}