I believe it is usually referrd to as code-switching

I wasn't looking so much for a generic term for this backing-and-forthing as for a specific term for the mix of Hindi and English. I have Hispanic friends who call the language mix they speak "Spanglish." I just can't imagine that the Indians call it "code-switching" - but that ain't what you meant either.

I can see the argument for calling it laziness, but I see it also as inventing a whole new language as one goes along, with a certain set of tools at hand. Personally, I find it fascinating to listen to, and occasionally hear things expressed in Spanglish much more colorfully, or powerfully, or succinctly than either language alone could do. It's also fun.