Some i18n problems in Plasma

Hi. My installation of Plasma has several translation problems in Spanish. For example, in Konsole the menus as file appear in English, while the content of the menu and pop-up windows are in Spanish. The same thing happens with Kate and Dolphin.
And in the regional preferences the preferred language option appears empty (Spanish does not appear) and only allows me to add English.
Is there any way to solve this problem in Plasma? The translations have not yet been packaged in nixpkgs?

Nixos 18.9

My configuration.nix for plasma

# Select internationalisation properties.
    i18n = {
      consoleFont = "Lat2-Terminus16";
      consoleKeyMap = "es";
      defaultLocale = "es_ES.UTF-8";

  # Set your time zone.
    time.timeZone = "America/Montevideo";

# Enable the KDE Desktop Environment.
    services.xserver.displayManager.sddm.enable = true;
    services.xserver.desktopManager.plasma5.enable = true;
    services.xserver.displayManager.sddm.autoNumlock = true;

The problem is that translation files for kde Applications end up in the $out output, while only the $bin is installed into the system/user profile. This is a bug in nixpkgs. Not sure if this has been tracked already but I heard of the problem lately from a few people.