The use of the suffix -ki  -  even though it is an indeclinable clitic  -  comes to the area of pronouns. –ki creates equivalents to English relative clauses or independent possessive pronouns (of the type mine, yours, ours). –ki does not produce pronouns but generally adjectives. Instead, in the declined word it represents the pronoun which can be seen in all the following examples. -ki is actually a text book example of a pronoun according to its definition: it comes to the phrase to substitute a noun, it stands in the agglutinated word pro noun.

–ki is typically attached to genitive words and expressions of place or time.

Ayşe|nin|ki ‘the one that belongs to Ayşe’

bizim|ki ‘the one that belongs to us’

arkadaş|lar|ınız|ın|ki ‘ the one that belongs to your friends’

ön|ünüz|de|ki ‘the one that is in front of you’

dün|kü ‘that of yesterday’

İzmir|’de|ki ‘the one that is in Izmir.

Any pronominal form containing –ki can be further modified. It can take the plural –ler:

masa|da|ki|ler ‘those which are on the table’.

A case suffix can be further added either to the singular or the plural form (note that the pronominal –n- is used after –ki only in the singular):

ben|de|ki|n|e ‘to the one that I have’

ev|in|ki|ler|i ‘the ones belonging to the house (ACC)’

In addition, the markers ile, -ce and –siz can be added to a word with –ki:

sokak|ta|ki|yle ‘with the one on the street’

The clitic –ki is like a full stop in a word. What is not usually possible in Turkish morphology, like doubled plural marking or the same case ending repeated twice can be found in words with –ki.

masa|lar|da|ki|ler ‘the ones that are on the tables’

ev|de|ki|ler|de ‘in the ones in the house’

Even though the morphology seems complicated the meaning is quite practical and ordinary. The same can be said about the example with two –ki’s.

ev|de|ki|ler|in|ki ‘the one belonging to those at home’.

(I used the usual web sites, Lewis 1969 and Göksel – Kerslake 2004.)

This may be a helpful addition to your post..

(locative -da/-de  + ki ) + noun => noun +  prepositional phrase (on, in, under,between)

Turkish ---------------------------->English

köşedeki ev - the house on the corner

Sıvıdaki moleküller - the molecules in the liquid

Yer altındaki su - the water under the ground

Sonuçlar arasındaki fark - the difference between the results

Thank you for reading it, scalpel.

If we need to put all –ki phrases under the same headline it should be “Equivalents to English relative clauses”. This is the explanation that Wikipedia article writer has used (I didn’t look further what his/her sources were). In a way it makes sense if you just imagine some dropped elements. A different question is whether you always need to explain everything through English grammar.

In its morphological transparency it find it a very fascinating structure.

The first impression of Turkish personal pronouns is that you hardly ever see them, except in the beginners’ translation attempts  -  soon deleted by the teachers. According to statistics, the impression seems to be only partly true. I took a look at word frequencies in English and Turkish. I don’t know if the materials are comparable, but surprisingly ben and o are among the ten most usual words in Turkish just like I and both he and it are in English. sen, though, is much less frequent than you (despite of the many meanings of the latter). If we also ignore o because lack of gender may create the wrong image, I still have ben in my hands and I can’t understand its high rank. Maybe one of the natives can explain it.

Personal pronouns in subject position are usually dropped. The detailed system of personal verb conjugation gives a chance to this. At least in certain types of texts like practical istructions pronouns in object position also have to go. When ben, sen, o… become visible in a sentence there is usually a reason for it. This has been studied by scholars. Most of the cases mentioned in grammars are intuitively obvious even for a learner, like signalling change of topic, sentence stress or contrasts between possible situations or NP referents.

A couple of syntactic reasons for showing the personal pronoun should be mentioned, though:

1. The referent of the 3^rd person genitive marked pronoun is always someone else than the subject of the clause. There is a crucial difference between the sentences

Semra onun anahtarlarını kaybetmış

Semra anahtarlarını kaybetmış.

2. You have to show the pronoun when the 3^rd person subject has been introduced in another syntactic position in the previous sentence:

Kitabı Zerrin’e verdim. O ne zamandır onu okumak istiyordu.

(Göksel – Kerslake, Turkish: a Comprehensive Grammar 2005. Enç, an article in Studies in Turkish Linguistics 1986.)

Is

         ?çoğu insanlar

or

         ?çoğu insan

a correct alternative for

         insanların çoğu

for the meaning ´most people´?

çoğu insan or insanların çoğu

scalpel, thanks.

A pro noun by definition is something that represents a noun, stands for it, takes its place.

What makes a pronoun in Turkish is often the third person possessive suffix. It attaches to adjectives and adverbs. Once POSS is added the word can be further declined. The use of POSS makes it possible to make pronouns out of many kinds of adjectives, not only those which we got used to in other languages.

         Öğrencilerin altısı sigara içmiyor. ‘Six (students) of the students don’t smoke.’
         Sarısını satın aldım. ‘I bought the yellow (shirt).’

What I am trying to say is maybe better than talking about Turkish pronouns we should talk about pronominal use of words. Or non-verbs which may have as well a) noun-like, b) adjectival or c) pronominal use.

         a) 4 büyükten en iyisi hangisi?
         b) Büyük oğlum 20 yaşında.
         c) Baba bunların büyüğüne para verdi.

Not sure if these are good examples...

Birisi iyi - One of them is good

Sarısı iyi - The yellow one is good

Soldaki iyi - The one on the left is good

Beğendiğin iyi - The one you like is good

First, I disagree with you on 4, it should be 3. (FB, GS, BJK)  

Second, the answer to this question always is: FB  

Scalpel, sanırım FB´yi tutuyorsun 

I admire the expressing power of 3rd sg POSS. Where does it refer actually? To the Platonic world of ideas. I´m not joking.