Hindi is Not Our National Language

According to the constitution that came into effect on 1950 January 26th, Hindi and English are the official languages of the Union. After 15 years (from 1965 January 26th onwards), Hindi would be the only official language.

Lal Bahadur Sastry introduced the bill The Official Languages Act, 1963 (which later amended in 1967), which provides for continuing the use of English in official work even after 25th January 1965.

In late 50s and early 60s, in Tamilnadu, there was a movement against Hindi. Tamilians did not like to be forced to learn Hindi. At that time, Nehru promised them that English would continue to be the official language, eventhough only one state (Tamilnadu) is asking for that. This was one reason, and not the only reason for the bill introduced by Lal Bahadur Sastry.

Debate in Rajya Sabha in September 1959

Debate in Parliament on the report of the Committee of Parliament on Official Languages. The then Prime Minister, Shri Jawahar Lal Nehru assured the House that neither will there be any hindrance on the use of English as an associate language nor will there be fixed any time limit for it. All the languages of India are equally respected and are our National Languages.

Neither the Constitution of India, nor any Indian law defines any National Language. If we take what Jawaharl Lal Nehru said in Rajya Sabha, then all the 22 scheduled languages can be considered as the National Languages. The 22 schedule languages defined by Indian Constitution are

Assamese, Bengali, Bodo, Dogri, Gujarati, Hindi, Kannada, Kashmiri, Konkani, Maithili, Malayalam, Manipuri, Marathi, Nepali, Oriya, Punjabi, Sanskrit, Santali, Sindhi, Tamil, Telugu and Urdu.

Update: On Jan 25th 2010, Gujarath High court gave ruling that, Hindi is not our National language.

References:
http://india.gov.in/knowindia/official_language.php
http://rajbhasha.nic.in/eventseng.htm
http://en.wikipedia.org/wiki/Official_languages_of_India
The Insider by P.V.Narasimha Rao