Check out new language_select element in Form API

This is already considered. Thisis wah tLanguageSelectWigdet.php contains:

  public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state): array {
    ...
    $element['value'] = [
      // Using 'language_select' would add dependency on core Language module.
      '#type' => 'select',
      ...
    ];

    return $element;
  }