In the initial writing of the article “Hindi, English or Nothing: Politics of India’s National Languages“, this author made an error, using the terms “official language” and “national language” interchangeably at one point. The mistake is deeply regretted. Since this blog aims to be a credible source of information and analysis, it must own up to its mistakes. By the way, thanks to Achal Kathuria for pointing it out.
There remains considerable confusion over the clear distinction between Official and National Language, to the extent that Gujarat High Court had to rule on it 2010. Even now, it seems there are no good legal definitions on the subject. Here is a good way to understand it: