The word kendi is the reflexive pronoun in Turkish. It is used with personal suffixes when used as a pronoun.

Conjugation of Kendi	Singular	Plural
First person	kendim	kendimiz
Second person	kendin	kendiniz
Third person	kendi(si)	kendileri

The most common translation of kendi is 'self', as in 'himself', 'ourselves', 'myself'. Notice in the third person singular form, the personal suffix is sometimes dropped. This is likely due to the general rule in Turkish which states lack of suffix indicates third person singular.

Also, suffixed forms of kendi can and usually do take case suffixes, for example kendilerini, kendimden, kendimizde, kendisine, etc.

Bunu kendim yapabilirim.	I can do this myself.
Kendinizi çok yordunuz mu?	Did you tire yourselves much?

Kendi can also be used without personal suffixes to modify nouns, in which it functions as an adjective. Then kendi means something like x's own.

Bu, Kamil'in kendi fikriydi.	This was Kamil's own idea.
Sen kendi evinde mi oturuyorsun?	Do you live at your own house?

There is another unique construction in which kendi is duplicated with dative suffix. Kendi kendi--e conveys a very specific meaning of completing the action alone. It is translated as 'by --self/selves'

Akşam yemeğini kendi kendime pişirdim.	I cooked the dinner by myself.
Ödevi kendi kendinize yapmalısınız.	You should do the homework by yourselves.

Breakdown of Ödevi kendi kendinize yapmalısınız.