ösüm

/ øsym /

Cases

SingularPluralWhen to use it
nominative ösüm the height ösümle the heights the plain dictionary form — the doer of the sentence
genitive ösümnü the height's ösümleni the heights' the owner — whose it is
accusative ösümnü the height (as the object) ösümleni the heights (as the object) a specific, known object — whom or what
dative ösümge to the height ösümlege to the heights direction or recipient — to where, to whom
locative ösümde at / in the height ösümlede at / in the heights where it is; also having — mende bar, "I have it"
ablative ösümden from the height ösümleden from the heights 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 ösümüm my height ösümlerim my heights
your ösümüŋ your height ösümleriŋ your heights
his / her ösümü his / her height ösümleri his / her heights
our ösümübüz our height ösümleribiz our heights
you all's ösümügüz you all's height ösümlerigiz you all's heights
their ösümleri their height ösümleri their heights

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