jay

/dʒaj/

Cases

SingularPluralWhen to use it
nominativejaythe summerjaylathe summersthe plain dictionary form — the doer of the sentence
genitivejaynıthe summer'sjaylanıthe summers'the owner — whose it is
accusativejaynıthe summer (as the object)jaylanıthe summers (as the object)a specific, known object — whom or what
dativejayğato the summerjaylağato the summersdirection or recipient — to where, to whom
locativejaydaat / in the summerjayladaat / in the summerswhere it is; also having — mende bar, "I have it"
ablativejaydanfrom the summerjayladanfrom the summerswhere 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
myjayımmy summerjaylarımmy summers
yourjayıngyour summerjaylarıngyour summers
his / herjayıhis / her summerjaylarıhis / her summers
ourjayıbızour summerjaylarıbızour summers
you all'sjayığızyou all's summerjaylarığızyou all's summers
theirjaylarıtheir summerjaylarıtheir summers

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