Not sure if you can rename them, but i do know there is a file that you can edit and put any names you want for future diggles (ofcourse it's gonna choose randomly from the list of your created words)

The file can be found under:
.\Diggles The Myth of Fenris\data\Scripts\classes\zwerg\names.txt

The default file has a whopping 1931 names in it, 969 male and 962 female.

Thx for reply !

You can directly rename them ingame.
While in the game go into the Dwarf menu (above the Techtree menu) and there in the Family tab
On the left side you can klick on the name and write whatever you want

Cool, that´s working, thanks !