Merhaba

when i learn in future lesson i noitce that its many verbs have (ð) after we put the suffix (ecek)

like (gideceðim)

iwant to know when  ican put y or  ð infuture tense

teþkkürler

Your question is a general question not specific to future tense.

Let´s put it this way:

When a word ends with k, in what cases do we need to apply k to ð mutation?

Answer:

When you add a suffix that starts with a vowel, k mutates to ð, othwersise it doesn´t change.

Examples:

Ayak = foot

Ayaðým = my foot (after suffix -ým which starts with vowel ý)

Balýk = fish

Balýða = to the fish (after suffix -a which starts with vowel a)

Yatak = bed

Yataða = to the bed (after suffix -a which starts with vowel a)

Yatakta = in the bed (after suffix -ta which starts with consonant t)

Now if we analyze the future tense:

You add -acak/-ecek tense suffix to the verb stem first and now we have an example of the general case I talked above)

When you have add personal suffixes to -acak/ecek, and you need to pay attention to whether it starts with a vowel or consonant.

Personal suffixes are:

-im (1st person sing. starts with vowel)

-sin (2nd person sing. starts with consonant)

-. (no suffix for 3rd person sing)

-iz (1st person pl. starts with vowel)

-siniz  (2nd person pl. starts with consonant)

-ler  (3rd person pl. starts with consonant)

So for example:

Gelecek = come+future

Geleceðim = I will come (k to ð mutation)

Geleceksin = you will come (no change)

Gelecek = he/she/it will come (no change)

Geleceðiz = we will come (k to ð mutation)

Geleceksiniz = you will come (no change)

Gelecekler = they will come (no change)

The rule has  exceptions...

Most of the monosyllabic words don´t follow the rule:

Kýrk+a =  kýrka 

Irk+ý =  Ã½rký

Çek+e = çeke

Ok+um =okum

Ak+ý = aký

but

çok+u = çoðu

And when k follows letter n it changes to g, not ð, for example:

renk + -i = rengi and NOT renði

Good point but not always.

Denk -- deng-i

Cenk -- ceng-e (to the battle)

but Cenk-e -- to Cenk (when it is a person´s name)

Bank -- bank-a

Künk -- künk-e

Tank -- tank-a

çok teþkkürlar