This is unlikely IMO. There is no local Kannada-English dialect and even Kannada speakers with weak English would know how to spell it. My guess is it’s becaus

This is unlikely IMO. There is no local Kannada-English dialect and even Kannada speakers with weak English would know how to spell it. My guess is it’s because English (Canada) comes first, before English (United Kingdom) and English (United States), in the list and most people in India are just selecting the first one (en-ca) without preference to any locale.