On LibreOffice version 5.1.6.1 i can’t check grammar and orthography in German, although I had a custom installation including German. But Spanish is present, although I didn’t opt for THAT. Also, the language tool file oxt 3.5 doesn’t install. What to do ?
. . . same thing for version 5.2.3 for WINDOWS, btw ~~~ 
. . . & I even installed JAVA, on request of the installer of Version: 5.2.3.3 (x64). It simply doesn’t work
Von Reiter an der oberen Seite des LibreOffice Fensters von
Extras zu
Optionen zu
Spracheinstellungen
English:
Tools
Options
Language Settings
navigieren.
hier kann man alles einstellen.