GoodThis is the literal meaning of the word "accha". It’s used in a similar way as the word "good" is used in English. For example, when asked how you’re feeling, you could reply “bahut accha hai” to convey that you’re feeling very good. Accha is also used in a similar context to indicate that something is good. “Yeh kitab accha hai” (This book is good).
Acknowledgement -- I See, I UnderstandWhen accha is said in a neutral tone at intervals during a conversation, it’s a way of acknowledging what the other person is saying. “I’m late for work today because I had so many problems along the way”. “Accha”. “Firstly, I left my wallet at home.” “Accha”. “After I went home and got it, I missed my train”. “Accha”.
Agreement -- Okay
When accha is repeated in quick succession during a conversation, it means that the person is agreeing with what’s being said. In this situation, "accha" sounds more like “achchacha”. “I’’ll be in the city next week and we should catch up. How about we go to dinner and see a movie? I can meet you at 7 p.m.” “Achchacha” (Okay, okay).
Note that Indians have a habit of repeating words to add emphasis to them. More often than not, when okay is said in agreement to something, it will be said not once but two or three times in a row!
Surprise -- Oh? Really?
When expressed in a tone of voice that rises sharply at the end, accha can be used as a statement of surprise. “My phone got stolen.” “Accha?” (Oh? Really?).
As you can imagine, it's very important to pay attention to the intonation of whoever is speaking, so as to understand the right meaning of the word accha. It would be terrible to mistakenly think that someone was replying "good" in response to a phone being stolen, when in fact they were expressing surprise!