In Turkish, according to the grammatical structure two vowels can not  come together. That’s why when we want to add a suffix which starts with a vowel, to a word which finishes with a vowel, we have to use buffer consonant.

In Turkish, there are two buffer consonants ;  “y, n “

y is the main buffer consonant and most used one.

n  buffer :

-      is used if we want to add a suffix to the pronouns.

Bu + u  --> Bu-n-u  : bunu

O + a   --> O-n-a    : ona

-      is used if we want to add a condition suffix ( -a –e – i – de –den) to the possesion suffix. Shortly it is used if we want to add a condition suffix to a noun phrase.

Fakirin evi-n-i satmışlar . ( They sold the house of the poor (one) )

Çocuğun kitabı-n-ı aldık.  ( We bought the book of the child)

Ağrı Dağı-n-ı göreceğim  (  I will visit Ağrı mountain)

-      is used if we want to add a suffix to make a noun phrase.

Ali - n – in kalemi à Ali’nin kalemi ( Ali’s pencil)

Kasaba-n-ın sıcağı ( the hot weather of the town)

For all situations except given above, - y buffer will be used.

Kedi+y+i getir --> Kediyi getir.  ( Bring the cat.)

Silgi+y+i kaybettim. -->  Silgiyi kaybettim. ( I have lost the eraser.)