tukum

/ tuqum /

Cases

SingularPluralWhen to use it
nominative tukum the family name tukumla the family names the plain dictionary form — the doer of the sentence
genitive tukumnu the family name's tukumlanı the family names' the owner — whose it is
accusative tukumnu the family name (as the object) tukumlanı the family names (as the object) a specific, known object — whom or what
dative tukumğa to the family name tukumlağa to the family names direction or recipient — to where, to whom
locative tukumda at / in the family name tukumlada at / in the family names where it is; also having — mende bar, "I have it"
ablative tukumdan from the family name tukumladan from the family names 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 tukumum my family name tukumlarım my family names
your tukumung your family name tukumlarıng your family names
his / her tukumu his / her family name tukumları his / her family names
our tukumubuz our family name tukumlarıbız our family names
you all's tukumuğuz you all's family name tukumlarığız you all's family names
their tukumları their family name tukumları their family names

The overlap in the last rows is real, not a mistake: tukumları can mean "his / her family names", "their family name", or "their family names" — context decides.