harf

/xarf/

Cases

SingularPluralWhen to use it
nominativeharfthe letterharflathe lettersthe plain dictionary form — the doer of the sentence
genitiveharfnıthe letter'sharflanıthe letters'the owner — whose it is
accusativeharfnıthe letter (as the object)harflanıthe letters (as the object)a specific, known object — whom or what
dativeharfhato the letterharflağato the lettersdirection or recipient — to where, to whom
locativeharfdaat / in the letterharfladaat / in the letterswhere it is; also having — mende bar, "I have it"
ablativeharfdanfrom the letterharfladanfrom the letterswhere 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
myharfımmy letterharflarımmy letters
yourharfıngyour letterharflarıngyour letters
his / herharfıhis / her letterharflarıhis / her letters
ourharfıbızour letterharflarıbızour letters
you all'sharfığızyou all's letterharflarığızyou all's letters
theirharflarıtheir letterharflarıtheir letters

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