This is the 6204th most frequent Arabic word.
for
The Arabic word for "for" is "لِـ" (li), meaning "intended for" or "in order to benefit."
In this sentence, the word 'لـ' (for) is used to indicate the purpose or recipient of the action of buying a gift.
أنا أشتري هدية لصديقي.
I am buying a gift for my friend.
Here, the word 'لـ' (for) shows who benefits from the usefulness of the book.
هذا الكتاب مفيد لي.
This book is useful for me.
In this case, 'من أجل' (for) expresses the goal or reason behind performing the action of studying Arabic.