Little correction: the correct language packages for Croatian as a reference are here:
nebojsa@momcilo-desktop:~$ dpkg -l | grep -e "-hr" ii firefox-locale-hr 66.0.2+build1-0ubuntu0.18.04.1 amd64 Croatian language pack for Firefox ii gnome-getting-started-docs-hr 3.28.2-0ubuntu0.1 all Help a new user get started in GNOME (Croatian) ii gnome-user-docs-hr 3.28.2+git20180715-0ubuntu0.1 all GNOME user's guide (Croatian) ii hunspell-hr 1:6.0.3-3 all Croatian dictionary for hunspell ii hyphen-hr 1:6.0.3-3 all Croatian hyphenation patterns ii language-pack-gnome-hr 1:18.04+20180712 all GNOME translation updates for language Croatian ii language-pack-gnome-hr-base 1:18.04+20180712 all GNOME translations for language Croatian ii language-pack-hr 1:18.04+20180712 all translation updates for language Croatian ii language-pack-hr-base 1:18.04+20180712 all translations for language Croatian ii libreoffice-l10n-hr 1:6.0.7-0ubuntu0.18.04.2 all office productivity suite -- Croatian language package ii thunderbird-locale-hr 1:60.6.1+build2-0ubuntu0.18.04.1 amd64 Croatian language pack for Thunderbird -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-control-center in Ubuntu. https://bugs.launchpad.net/bugs/1823778 Title: Unable to set Serbian as Language Status in gnome-control-center package in Ubuntu: New Bug description: Affected: 18.04.2 (did not try earlier versions of 18.04 series) Not affected: 16.04 - any version (UI was different) Preparation steps: 1. open gnome control center 2. open Region & Language 3. open Manage installed languages 4. open Install/Remove languages 5. select Serbian, click Apply 6. provide credentials for sudo installation 7. wait for installation to complete 8. click Close What is wrong: 1. open gnome control center 2. open Region & Language 3. click Language selection 4. Serbian is not visible Notes: - Serbian is visible for the Formats selection - Any other language I thought of: (Macedonian, Croatian, Bosnian, Russion...) simple work. Here is some dpkg output on installaed packages matching sr (Serbian) or hr (Croatian). ii firefox-locale-sr 66.0.2+build1-0ubuntu0.18.04.1 amd64 Serbian language pack for Firefox ii gnome-getting-started-docs-sr 3.28.2-0ubuntu0.1 all Help a new user get started in GNOME (Serbian) ii gnome-user-docs-sr 3.28.2+git20180715-0ubuntu0.1 all GNOME user's guide (Serbian) ii hunspell-sr 1:6.0.3-3 all Serbian dictionary for hunspell ii hyphen-sr 1:6.0.3-3 all Serbian hyphenation patterns ii language-pack-gnome-sr 1:18.04+20180712 all GNOME translation updates for language Serbian ii language-pack-gnome-sr-base 1:18.04+20180712 all GNOME translations for language Serbian ii language-pack-sr 1:18.04+20180712 all translation updates for language Serbian ii language-pack-sr-base 1:18.04+20180712 all translations for language Serbian ii libreoffice-l10n-sr 1:6.0.7-0ubuntu0.18.04.2 all office productivity suite -- Serbian language package ii thunderbird-locale-sr 1:60.6.1+build2-0ubuntu0.18.04.1 amd64 Serbian language pack for Thunderbird nebojsa@momcilo-desktop:~$ dpkg -l | grep -e "-hr" rc language-pack-gnome-hr-base 1:18.04+20180712 all GNOME translations for language Croatian rc language-pack-hr-base 1:18.04+20180712 all translations for language Croatian ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: gnome-control-center 1:3.28.2-0ubuntu0.18.04.2 ProcVersionSignature: Ubuntu 4.18.0-17.18~18.04.1-generic 4.18.20 Uname: Linux 4.18.0-17-generic x86_64 ApportVersion: 2.20.9-0ubuntu7.6 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Mon Apr 8 20:10:54 2019 InstallationDate: Installed on 2019-04-06 (2 days ago) InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210) SourcePackage: gnome-control-center UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-control-center/+bug/1823778/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp