You can check if a PO file is valid with the following command:

        msgfmt -c -o /dev/null <po file>
      

The following errors were found in cura 's PO files:

gettext: resources/i18n/cs_CZ/cura.po: can't guess language
gettext: resources/i18n/cura.pot:2899: duplicate message definition...
resources/i18n/cura.pot:2895: ...this is the location of the first definition
msgfmt: found 1 fatal error
gettext: resources/i18n/de_DE/cura.po: can't guess language
gettext: resources/i18n/es_ES/cura.po: can't guess language
gettext: resources/i18n/fi_FI/cura.po: can't guess language
gettext: resources/i18n/fr_FR/cura.po: can't guess language
gettext: resources/i18n/hu_HU/cura.po: can't guess language
gettext: resources/i18n/it_IT/cura.po: can't guess language
gettext: resources/i18n/ja_JP/cura.po: can't guess language
gettext: resources/i18n/ko_KR/cura.po: can't guess language
gettext: resources/i18n/nl_NL/cura.po: can't guess language
gettext: resources/i18n/pl_PL/cura.po: can't guess language
gettext: resources/i18n/pt_BR/cura.po: can't guess language
gettext: resources/i18n/pt_PT/cura.po: can't guess language
gettext: resources/i18n/ru_RU/cura.po: can't guess language
gettext: resources/i18n/tr_TR/cura.po: can't guess language
gettext: resources/i18n/zh_CN/cura.po: can't guess language
gettext: resources/i18n/zh_TW/cura.po: can't guess language
      

Please ask the translator (identified by the Last-Translator field in the PO file), the language team (identified by the Language-Team field) or debian-i18n for a fix.