"What about your mother tongue?" I'm asked by a friend one more time. There in the office, crouched over the desk, still staring at the computer screen, I recollect all the main points in no particular order (I've done this a few times before). A final 'botlike' mental Google search (in true millennial fashion): 'Mother+tongue,' I process. The first page of links my memory throws up are all about dadi. 'Grandmother tongue,' I whisper, then turn to him to state my case.