Why is the Yorkshire dialect called 'Tyke'?

From Wikipedia:

The Yorkshire dialect refers to the varieties of English used in the Northern England historic county of Yorkshire. Those varieties are often referred to as Broad Yorkshire or Tyke.

Why is the Yorkshire dialect called 'Tyke'? Can the accent be referred to as tyke as well?

ODO's definition of tyke includes a number of negative senses. Is this sense also derogatory?

Solution 1:

As OED says, tyke originally came from Old Norse tík - female dog, bitch. It's not exclusively reserved for Geordies (or people from Newcastle), but as OED also points out, it often does have that sense - "perhaps originally opprobrious; but now accepted and owned [by them]".

I recall that my grandmother, who never lived anywhere but Sussex for all her 99 years, used to sometimes call me a dirty little tyke. I doubt all "Novocastrians" are happy to be thus called.

FWIW here's the full relevant OED entry...

3. A nickname for a Yorkshireman: in full Yorkshire tyke.
(Perhaps originally opprobrious; but now accepted and owned.
It may have arisen from the fact that in Yorkshire tyke is in common use for dog.)

...but no mention of the word being used to mean the Yorkshire accent/dialect.