WP_Locale_Switcher::switch_to_locale( string $locale, int|false $user_id = false ): bool

75	public function switch_to_locale( $locale, $user_id = false ) {76		$current_locale = determine_locale();77		if ( $current_locale === $locale ) {78			return false;79		}80 81		if ( ! in_array( $locale, $this->available_languages, true ) ) {82			return false;83		}84 85		$this->stack[] = array( $locale, $user_id );86 87		$this->change_locale( $locale );88 89		/**90		 * Fires when the locale is switched.91		 *92		 * @since 4.7.093		 * @since 6.2.0 The `$user_id` parameter was added.94		 *95		 * @param string    $locale  The new locale.96		 * @param false|int $user_id User ID for context if available.97		 */98		do_action( 'switch_locale', $locale, $user_id );99 100		return true;101	}