Dialect
The label dialect refers to any distinctive speech variety associated with the people of a particular region (regional dialect) or a social group (social dialect). English has a number of regional dialects. The English spoken in London, for example, is somewhat different from the English spoken in New York or Chicago.
There are also plenty of social dialects. A taxi driver, for example, does not speak like a school teacher. Even standard English is merely a dialect of English, but it does enjoy a very special status.
Direct question
A direct question is a sentence which has the form of a question expecting an answer.
Examples are:
What are you doing?
What is the capital of South Africa?
Are you going to Susie’s birthday party?
Discourse marker
A discourse marker is a word or a phrase which serves chiefly to keep a conversation flowing smoothly. Examples are: yes, so, of course, nevertheless, well etc. A discourse marker is only weakly linked to an adjoining sentence. Sometimes it is not linked at all.
Double negative
Any grammatical construction in which two or more negative words appear in a single clause. Double negatives are common in most vernacular forms of English, but it is considered inappropriate in standard English.
Note that a double negative is not equivalent to a positive. For example, the sentence ‘I didn’t say nothing’ does not mean that ‘I said something’. It merely happens to be a non-standard, yet familiar and understandable way of saying ‘I didn’t say anything’.