tab1.page.html

<ion-header>
  <!--  other stuff -->
</ion-header>

<ion-content>
  <ion-card class="welcome-card">
    <!--  other stuff -->
    <ion-card-content>
      <p translate [translateParams]="{ lang: language }">tab1.invite</p>

      <ion-item> <!-- add this block -->
        <ion-label translate>Language</ion-label>
        <ion-select [(ngModel)]='language' (ionChange)='languageChange()' [placeholder]='"tab1.languageChangePlaceholder" | translate'>
          <ion-select-option value='ru'>Russian</ion-select-option>
          <ion-select-option value='en'>English</ion-select-option>
        </ion-select>
      </ion-item> <!-- add this block (end) -->
    </ion-card-content>
  </ion-card>

  <!--  other stuff -->
</ion-content>