gelme-s-i-n-i gelme = the noun form of the verb gelmek i.e. "to come, coming" s = buffer letter "only used with the 3rd person suffix" in case there is a vowel. i.e. his/her door, onun kapıSı. i = 3rd person suffix "ı,i,u,ü" i.e. his/her door/house/box/grape, onun kapıSI/evİ/kutuSU/üzümÜ. *if the word ends in a vowel add s then the suffix. n = buffer letter "used on Nouns which already have been suffixed". and again if it ends in a vowel use N to add another suffix like: i = accusative suffix, i.e. i want his/her house onun evi-Nİ isterim
another question ... so we use the buffer "n" to separate between the suffixes that are in one word ( vowels facing each other case only) and to separate between the 2 vowels that are located in the end of a word and in the beginning of the following word .. so why didn't we add the buffer n between evini -n isterim
gelme: coming (participle of "gelmek", to come).
gelmesi: her coming
gelmesini: her coming (accusative) - because it is the object of "istemek" (to want)
What do you want? I want her coming. Whose coming? My mother's coming.
I want my mother's coming. Annemin gelmesini istiyorum.
That sounds like "I want to come my mother", which doesn't work since "gelmek" is an intransitive verb, and your mother isn't the real object of the sentence. If the subject of the sentence (here, "ben") is different than the subject of the subordinated verb (here, "annem"), then you need to express the second verb as the object of your sentence, and make it possessed by the subject of the second verb.