cer

/ dʒer /

Cases

SingularPluralWhen to use it
nominative cer the land cerle the lands the plain dictionary form — the doer of the sentence
genitive cerni the land's cerleni the lands' the owner — whose it is
accusative cerni the land (as the object) cerleni the lands (as the object) a specific, known object — whom or what
dative cerge to the land cerlege to the lands direction or recipient — to where, to whom
locative cerde at / in the land cerlede at / in the lands where it is; also having — mende bar, "I have it"
ablative cerden from the land cerleden from the lands 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 cerim my land cerlerim my lands
your cering your land cerlering your lands
his / her ceri his / her land cerleri his / her lands
our ceribiz our land cerleribiz our lands
you all's cerigiz you all's land cerlerigiz you all's lands
their cerleri their land cerleri their lands

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