It seems that no translations are included in the .desktop files. Looking at e.g. /usr/share/applications/libreoffice-writer.desktop
[...]
Name=LibreOffice Writer
GenericName=Word Processor
GenericName[en]=Word Processor
Comment=Create and edit text and graphics in letters, reports, documents and Web pages by using Writer.
Comment[en]=Create and edit text and graphics in letters, reports, documents and Web pages by using Writer.
InitialPreference=5
X-Ayatana-Desktop-Shortcuts=X-New
[X-New Shortcut Group]
Name=New Document
Name[en]=New Document
[...]
It seems that no translations are included in the .desktop files. Looking at e.g. /usr/share/ applications/ libreoffice- writer. desktop
[...] en]=Word Processor Desktop- Shortcuts= X-New
Name=LibreOffice Writer
GenericName=Word Processor
GenericName[
Comment=Create and edit text and graphics in letters, reports, documents and Web pages by using Writer.
Comment[en]=Create and edit text and graphics in letters, reports, documents and Web pages by using Writer.
InitialPreference=5
X-Ayatana-
[X-New Shortcut Group]
Name=New Document
Name[en]=New Document
[...]