Could you add Kumyk (ISO-639-3: kum) so that it can be selected from the drop-down menu, and a spellchecker can be installed.
Work ongoing on spellchecker here:
Eike, Can you look at this?
The language doesn't exist in LO yet
Eike Rathke committed a patch related to this issue.
It has been pushed to "master":
added Kumyk [kum-RU] to language list, fdo#70089
The patch should be included in the daily builds available at
http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.