speak() {
    if (!Recognition.isSupported()) {
      return this;
    }
    const { speaking } = this.state;
    if (!speaking) {
      this.recognition.start();
      this.setState({
        speaking: true,
        inputValue: ''
      });
    } else {
      this.setState({
        force: true
      });
      this.recognition.stop();
    }
    return this;
  }
toggle the recognition
@returns {Recognition}
@memberof Recognition
@public