telefon

/telefon/

Cases

SingularPluralWhen to use it
nominativetelefonthe telephonetelefonlathe telephonesthe plain dictionary form — the doer of the sentence
genitivetelefonnuthe telephone'stelefonlanıthe telephones'the owner — whose it is
accusativetelefonnuthe telephone (as the object)telefonlanıthe telephones (as the object)a specific, known object — whom or what
dativetelefongato the telephonetelefonlağato the telephonesdirection or recipient — to where, to whom
locativetelefondaat / in the telephonetelefonladaat / in the telephoneswhere it is; also having — mende bar, "I have it"
ablativetelefondanfrom the telephonetelefonladanfrom the telephoneswhere it comes from; also "than" when comparing
When to use each case
nominative
the plain dictionary form — the doer of the sentence
genitive
the owner — whose it is
accusative
a specific, known object — whom or what
dative
direction or recipient — to where, to whom
locative
where it is; also having — mende bar, "I have it"
ablative
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
mytelefonummy telephonetelefonlarımmy telephones
yourtelefonungyour telephonetelefonlarıngyour telephones
his / hertelefonuhis / her telephonetelefonlarıhis / her telephones
ourtelefonubuzour telephonetelefonlarıbızour telephones
you all'stelefonuğuzyou all's telephonetelefonlarığızyou all's telephones
theirtelefonlarıtheir telephonetelefonlarıtheir telephones

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