This is the 23rd most frequent Vietnamese word.
mà
The Vietnamese word "mà" can mean "but," "that," "which," or serve as a connector or emphasis word, depending on context.
The word 'mà' is used here as a relative pronoun connecting the noun 'cuốn sách' (the book) with the clause 'tôi yêu thích nhất' (I like the most).
Đây là cuốn sách mà tôi yêu thích nhất.
This is the book that I like the most.
In this sentence, 'mà' functions to introduce a contrast or unexpected outcome following the first clause.
Tôi định đi chơi mà trời lại đổ mưa.
I was planning to go out, but then it started raining.
Here, 'mà' signifies the condition under which the main action (talking) should not occur. It implies a connection between the action and the behavior.