I don’t believe that for the Dravidian languages mutual intelligibility is common. I’m a Tamil speaker and I can’t understand any Telugu or Kannada - it sounds like people speaking Tamil underwater in a dream.

Can someone with more linguistic background compare this to Roman languages for me.

Is this like saying Italian, French, Spanish are pretty much the same because they are Romamtic languages? Or English and German are interchangable, because English is a Germanic language?

Or, is much closer like British and American English- just mostly difference because of accents and dialects?

Trying to understand how different Indian subgroups of languages are.

>Is this like saying Italian, French, Spanish are pretty much the same because they are Romamtic languages? Or English and German are interchangable, because English is a Germanic language?

It really varies. Some languages, like Hindi, Gujarati, and Punjabi, are about as similar as Italian, Portuguese, and Spanish. In other cases the common languages can be very different. Telugu and Tamil, for instance, are probably much more like trying to go between English and German. Telugu and Kannada are kind of odd ducks. They're basically Dravidian languages that borrowed tons of their vocabulary from an Indo-European language (Sanskrit). That actually makes it a very good analogue for English, which is a Germanic language that spent a lot of time trying desperately to be a Romance language (French).

My understanding is that yes, to a very large extent, since they are dialects of the same language foundation, which is sanskrit and later prakrit.

No, you're referring to very broad language families. See my other post or www.ethnologue.com for accurate information.

It's a bit of a tricky business, because what counts as a language is often also determined by political decisions. Mutual comprehensibility is not a reliable criterion. However, modern linguistics uses pretty good sets of "soft" criteria for the classifications.

From personal experience, this is not really true, there are some languages that do maintain some sort of mutual comprehension, but the vast majority in India have no guarantee of that apart from a few choice root words. Speakers of a particular Dravidian language will almost certainly not be able to understand another, and you could make the same argument for Indo-Aryan languages with a very high percentage of success. It's like calling English and French the same language because they have some words that have a similar root. Or even English and German.