I hope I undestood it correctly, the reason is probably because of the difference between the suffixes. "ler" and "-im, -sin, -iz, -siniz" suffixes are not the same type of suffixes. "-ler" is a plural suffix, and the others are personal suffixes (or possessive). "Onlar" and "o" do not take personal suffixes, words for these are in the non suffix forms. -ler is added for "onlar" just to make the nouns plural. I hope I gave a right explanation.

 I guess there´s a typo here "kadının bardağıyla kızın bardağında..." and no comma.

here it´s "ile" (with/by/and) that is suffixed to "bardak" (glass),

bardak + ı + ile --> bardağıyla (there are rules that explains why it becomes "bardağıyla"),

and here "ile" does the "and" duty here which is equal to "ve" (and) ile = ve

There´s the same amount of milk in the woman´s glass and in the girl´s glass.

Please open threads about translations in the translation forum.

 I didn´t get what confuses you here CANLI.

 "Bana türkçe veya kürtçe öğretmeye zamanı olan biri var mı acaba, pratiğe ihtiyacım var. Eğer zamanınız varsa lütfen benimle iletişime geçin."

 It´s ok hehe. Usually the one that comes to your mind the first is correct. Probably you had heard it before.

 Bir oğlum var. The "u" drops there. There´s a rule about dropping vowels.

 It´s exactly the opposite

Bazı resimler (always plural)

Birkaç resim (always singular)

 "Bırak nefesim kalbinde yer bulsun. Bırak hayatım aşkında mahvolsun."

So it means that you, arabophones, are one step ahead of the others in learning turkish vocabulary.