TypeError: this.TTS.speak is not a function - Ionic V3

i have a problem with https://ionicframework.com/docs/native/text-to-speech
because this say me TypeError: this.TTS.speak is not a function.

help me !!

import { TextToSpeech } from '@ionic-native/text-to-speech/ngx';
import { Storage } from '@ionic/storage';

  selector: 'page-ubications',
  templateUrl: 'ubications.html',
export class UbicationsPage {
  text: string;
  rate: number;
  locale: string;
  datos: any;
  inicio: any;
  fin: any;
  ref: any;
  tipo: any;
  bandera: any;
  myForm: FormGroup;
  @ViewChild('sku') inputToFocus;
    public tts: TextToSpeech,
    private alertCtrl: AlertController,
    public pservice: PedidosServicesProvider,
    public loadingCtrl: LoadingController,
    public formBuilder: FormBuilder,
    public navCtrl: NavController,
    public navParams: NavParams
  ) {
    this.myForm = this.createMyForm();
    this.bandera = 0;
    this.text = 'Initial text';
    this.rate = 1;
    this.locale = 'en-US';
  private createMyForm() {
    return this.formBuilder.group({
      refere: ['', Validators.required],
  ionViewDidLoad() {
    console.log('ionViewDidLoad UBICACIONES');
    setTimeout(() => {
    }, 300);

  playText(t) {
        text: 'hello',
        rate: this.rate / 10,
        locale: this.locale,
      .then(() => console.log('Success'))
      .catch((reason: any) => console.log(reason));

Yes, this is to be expected. Cordova is not available in the browser and is only available once deployed to a device.