1. (British slang, esp. Asian, i.e. Indian, Pakistani, etc.)

Contraction of "isn't it", "isn't he/she", "aren't they", "isn't there" and many other end-of-sentence questions. For greatest effect use in places where it would make no sense whatsoever if expanded.

2. General positive exclamation meaning "yes, I agree!"

isn't it?

Contraction of 'isn't it' which has been used in London for about 40 years ATLEAST. (so stop attibuting it to all sorts of wierd groups of people like for example chavs) Used at the end of sentances in the same was as eh?, right? or you-get-me?

A derivative of "is it not", or more directly "isn't it". Often used at the end of a statement or word to give it emphasis, and simultaneously invite agreement.

Derives from the chav/townie/pikey sub-culture, but falsely over-labbeled on the British Asian Communities. Innit is a shortened version of is it not, in context, it would be "is it not?" which we can see is a question due to the required question mark and change in the pitch of the voice to indicate a question is being asked. Chavs, however, due to their lack of education (zero GCSEs) and ignorance towards learning English at school because "i already speaks it, innit", tend to, more often than not, use the term innit when a statement has been used, rather than a question.

Abreviation of isn't it (Is it not)
"Innit" is put at the end of a question or statement meaning either:
- Do you agree?
or
- Are you following me/Do you understand?

"Innit has classically been added at the end of a sentence that contains the verb "to be", as "ISn't it" obviously refers back to a conjugation of the this verb. (See example 1.)
These days though, "innit" can be used eventhough the verb in the main sentence is not a form of "to be". (See example 2)