I am pleasantly surprised to see Kannada and Karnataka mentioned. I am a Kannadiga from Bengaluru. As for street slang of the city, don't ignore the copious amounts of Urdu loan words!
As you might already know, the case with Kannada is more complex. Firstly, it has high amount of diglossia. Even with all the unnecessary, flowery Sanskrit loan words removed, the spoken form is greatly different from the written form. Next, the spoken language has many many regional variants, as with most languages in the world. Further, the spoken language varies according to social groups aka caste within the regions. One could even attempt to find variations based on economic status, aka rich to poor scale, but as an amateur linguist I don't find anything particularly noteworthy to hold such a classification, and, if anything, the variation is mostly confined to the tone of speech (not same as being tonal) and a bit of inflectional oddities rather than vocabulary. In modern times, the rich tend to use more English words which muddles the matter further. Beyond all this, there are about half a dozen languages that are identified as child languages of Kannada that are mostly associated with tribal groups living in forests and mountains. I guess this kind of diversity is expected of a language which is in continuous use for nearly two millennia.
For those intrigued and interested by this, I can't give any references on the internet beyond the wikipedia page because Kannada and Karnataka are severely underrated and underrepresented in Indian historical scene. Any work of worth written in English belong to the colonial times, with 1930s being the latest. The information in this post comes from knowledge acquired by reading books published, in Kannada, by language departments of universities of the state and the literary organization, and others are from personal experiences.
