This is the 14297th most frequent Turkish word.
okumalarının
"Your readings" or "the act of your reading."
In this sentence, 'okumalarının' is a possessive noun phrase referring to 'readings' (noun form of verb 'okumak') belonging to 'this book'.
Bu kitabın okumalarının çok keyifli olduğu söyleniyor.
It is said that the readings of this book are very enjoyable.
Here, 'okumalarının' refers to the noun 'readings' (the activity of reading) possessed by 'him/her'.
Onun okumalarının geliştiğini fark ettik.
We noticed that his/her readings had improved.
In this sentence, 'okumalarının' designates the noun formed as 'readings', associated possessively with 'students'.