Sometimes the words we say can sound harsh or demanding, even when that is not our intention. Mandarin has a way of softening requests or suggestions by adding the final particle ba 吧.
Using the final particle ba is equivalent to using a question tag (aren't you?) or making a suggestion in the form of "let's (do something)" - "let's go to the movies."
The final particle ba is always used at the end of a sentence.
When the speaker believes the listener will agree, the final particle ba is used to indicate probability. In this situation, dà gài 大概 can be used in the sentence.
Examples of the Final Particle Ba
Wǒmen zǒu ba.
Let's go, OK?
Nǐ gàosu tā ba.
You tell him, OK?
Nǐ (dàgài) hěn máng ba?
You are (probably) very busy, aren't you?