installer-prompt/scripts/change-system-language

#!/bin/bash

LANGUAGE_CODE="$1"
COUNTRY_CODE="$2"
LOCALE="${LANGUAGE_CODE}_${COUNTRY_CODE}.UTF-8"
LIBREOFFICE_CODE="$3"
ONLY_LXQT="$4"

# Special handling for language packs for Chinese
if [[ "$LANGUAGE_CODE" == "zh" ]]; then
    if [[ "$COUNTRY_CODE" == "CN" || "$COUNTRY_CODE" == "SG" || "$COUNTRY_CODE" == "MY" ]]; then
        LANG_PACK_SUFFIX="zh-hans"
    else
        LANG_PACK_SUFFIX="zh-hant"
    fi
else
    LANG_PACK_SUFFIX="$LANGUAGE_CODE"
fi

if [ -z "$ONLY_LXQT" ]; then
    apt-get -y install language-pack-gnome-"$LANG_PACK_SUFFIX" language-pack-kde-"$LANG_PACK_SUFFIX"
    # Install LibreOffice language pack only if LIBREOFFICE_CODE is provided
    # and it's not English without a specific variant
    if [[ "$LANGUAGE_CODE" != "en" ]] || [[ "$LANGUAGE_CODE" == "en" && ( "$COUNTRY_CODE" == "GB" || "$COUNTRY_CODE" == "ZA" ) ]]; then
        apt-get -y install libreoffice-l10n-"$LIBREOFFICE_CODE"
    fi
fi

locale-gen "$LOCALE"
update-locale LANGUAGE="$LOCALE" LANG="$LOCALE" LC_ALL="$LOCALE"
systemctl restart sddm