constructor(onChange = noop, onEnd = noop, onStop = noop, lang = 'en') {
    if (!instance) {
      instance = this;
    }
    this.state = {
      inputValue: '',
      lang,
      onChange,
      onEnd,
      onStop
    };

    this.onResult = this.onResult.bind(this);
    this.onEnd = this.onEnd.bind(this);

    this.setup();

    return instance;
  }
Creates an instance of Recognition.
@param {function} [onChange] callback on change
@param {function} [onEnd]  callback on and
@param {function} [onStop]  callback on stop
@param {string} [lang='en'] recognition lang
@memberof Recognition
@constructor