function togglePlayPause (which) {
			removeClass(play, `${t.options.classPrefix}play`);
			removeClass(play, `${t.options.classPrefix}replay`);
			removeClass(play, `${t.options.classPrefix}pause`);

			if ('play' === which) {
				addClass(play, `${t.options.classPrefix}pause`);
				playBtn.setAttribute('title', pauseTitle);
				playBtn.setAttribute('aria-label', pauseTitle);
			} else if('pse' === which) {
				addClass(play, `${t.options.classPrefix}play`);
				playBtn.setAttribute('title', playTitle);
				playBtn.setAttribute('aria-label', playTitle);
			} else {
				addClass(play, `${t.options.classPrefix}replay`);
				playBtn.setAttribute('title', playTitle);
				playBtn.setAttribute('aria-label', playTitle);
			}
		}
@private
@param {String} which - token to determine new state of button