qTranslate-XT и WooCommerce Subscriptions

Подскажите как правильно перевести поле "month" в коде ниже с помощью qTranslate-XT? Если в поле sprintf( _nx( 'day' вместо day вставлять [:ru]день[:uk]день[:] то не работает.

function wcs_get_subscription_period_strings( $number = 1, $period = '' ) {

    // phpcs:disable Generic.Functions.FunctionCallArgumentSpacing.TooMuchSpaceAfterComma
    $translated_periods = apply_filters( 'woocommerce_subscription_periods',
        array(
            // translators: placeholder is number of days. (e.g. "Bill this every day / 4 days")
            'day'   => sprintf( _nx( 'day',   '%s days',   $number, 'Subscription billing period.', 'woocommerce-subscriptions' ), $number ), // phpcs:ignore WordPress.WP.I18n.MissingSingularPlaceholder,WordPress.WP.I18n.MismatchedPlaceholders
            // translators: placeholder is number of weeks. (e.g. "Bill this every week / 4 weeks")
            'week'  => sprintf( _nx( 'week',  '%s weeks',  $number, 'Subscription billing period.', 'woocommerce-subscriptions' ), $number ), // phpcs:ignore WordPress.WP.I18n.MissingSingularPlaceholder,WordPress.WP.I18n.MismatchedPlaceholders
            // translators: placeholder is number of months. (e.g. "Bill this every month / 4 months")
            'month' => sprintf( _nx( 'month', '%s months', $number, 'Subscription billing period.', 'woocommerce-subscriptions' ), $number ), // phpcs:ignore WordPress.WP.I18n.MissingSingularPlaceholder,WordPress.WP.I18n.MismatchedPlaceholders
            // translators: placeholder is number of years. (e.g. "Bill this every year / 4 years")
            'year'  => sprintf( _nx( 'year',  '%s years',  $number, 'Subscription billing period.', 'woocommerce-subscriptions' ), $number ), // phpcs:ignore WordPress.WP.I18n.MissingSingularPlaceholder,WordPress.WP.I18n.MismatchedPlaceholders
        ),
        $number
    );
    // phpcs:enable

    return ( ! empty( $period ) ) ? $translated_periods[ $period ] : $translated_periods;
}