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 sonic-pi 's PO files:

source does not specify a priority
gettext: app/server/beam/tau/priv/gettext/en/LC_MESSAGES/errors.po: warning: Charset missing in header.
                                                                                                                    Message conversion to user's charset will not work.
gettext: etc/doc/lang/sonic-pi-tutorial-zh-Hans.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.