<input id="sliderman1" type="text" data-slider-min="0" data-slider-max="4" data-slider-step="1" data-slider-value="2" data-slider-ticks="[0, 4]"/>
<span id="sliderman1Value">3</span></span>

var values = ['None', 'Read', 'Speak', 'Test', 'Last'];
var formatter = (index) => values[index];

var slider = new Slider("#sliderman1", {formatter} );
slider.on("slide", function(sliderValue) {
document.getElementById("sliderman1Value").textContent = sliderValue;

});