dert

/ dert /

Cases

SingularPluralWhen to use it
nominative dert the grudge dertle the grudges the plain dictionary form — the doer of the sentence
genitive dertni the grudge's dertleni the grudges' the owner — whose it is
accusative dertni the grudge (as the object) dertleni the grudges (as the object) a specific, known object — whom or what
dative dertge to the grudge dertlege to the grudges direction or recipient — to where, to whom
locative dertde at / in the grudge dertlede at / in the grudges where it is; also having — mende bar, "I have it"
ablative dertden from the grudge dertleden from the grudges where it comes from; also "than" when comparing

The endings are the same ones the pronouns wear — that page explains when each case is used.

With an owner

One ownedSeveral owned
my dertim my grudge dertlerim my grudges
your dertiŋ your grudge dertleriŋ your grudges
his / her derti his / her grudge dertleri his / her grudges
our dertibiz our grudge dertleribiz our grudges
you all's dertigiz you all's grudge dertlerigiz you all's grudges
their dertleri their grudge dertleri their grudges

The overlap in the last rows is real, not a mistake: dertleri can mean "his / her grudges", "their grudge", or "their grudges" — context decides.