It's true that " 吧 ba '' is always put at the end of a sentence ends with "！'' to show that the person who's talking is not sure about what he/she just said. How to identify? When you see '' 應該 " used with " 吧 ！'' means the person 's not sure. However, "吧！'' can also used when someone encourage, invite or ask you to do something with them for them: 一起走吧！/ 一塊兒來吧！/一起去吧！/吃吧！

it's either a questioning or an encouraging particle 吧

You mean this word ' 吧' ? 1）Chinese particles Normally it's at the end of one sentence,it means agreed,approved,guessing or not sure. 大概是这个意思吧。 2) Noun It means bar for short. 3) Onomatopoeia It means cracking.

“ba”-“吧” It's always used at the end of a sentence, and it doesn't have any specific meaning by itself. It's more like a tone, indicating agreement, deduction, request, or command, etc.