bool flag = true;

private void Update()
    {
        valueY = lowpass().y;

        if (valueY <= -0.5f)
        {
            if(flag){
                 currentText.text = words[Random.Range(0, 5)];
                 flag = false;
            }
        }
        else if(valueY >= -0.7f)
        {
            if(flag){
                 currentText.text = words[Random.Range(0, 5)];
                 flag = false;
            }
        }else if (valueY == 0)
        {
                 flag = true;
        }
    }