National Link Language and Script
Bhārata cannot have a national language since Bhāratīyars speak different languages. However, Bhārata needs a national link language to facilitate communication between various ethnicities speaking various languages in the country. Many Bhāratīyars use and suggest English to be this link language, but it cannot be for two reasons. The first reason is that it is a matter of self-esteem, that despite having thousands of languages in the country and many that does not belong to any particular community, and many that may even be superior to English subjectively, we use a foreign language as our link language.
The second reason and perhaps the most important one, is a matter of cultural fit. English is not an efficient language for Bhāratīya ethos because there are no perfect English translations for many native words in culture, philosophy and arts. Thus, the continued use of English being the first language will drive Bhāratīyar away from their culture.
Sanskrit is a good candidate to be the national link language for the reason that it is the mother of most Bhāratīya languages. And of those language to whom Sanskrit isn't a mother — like Tamil, Telugu and many Northeast Bhāratīya languages — there is quite a good influence and adoption of Sanskrit words in their vocabularies. However, because Sanskrit national literacy is low and raising it will require time and effort, we need a temporary link language. Any Bhāratīya language is eligible to be this language, but Hindi has an advantage because of its national footprint, non belongingness to any particular community and similarities with Sanskrit in pronunciation and in the use of Devanagiri script, thus making the later transition to Sanskrit easier.
The sentiment of unfairness felt by some Bhāratīyar from the South and Northeast Bhārata when Hindi — a language from the Northern part of Bhārata — is made the national link language is understandable. However, I do not understand the alternative proposed by them — English — as this only aggravate the very sentiment they are using against Hindi. If they feel unfair because Hindi is from the northern part of Bhārata, then they should feel more unfair because English is from a place that is much farther away. But apparently they don't feel it.
There is a pattern generally seen in societies that people tend to be more compromising and accommodating to those closer to us than to those farther to us. For instance, you are more likely to spend money for your cousin than a stranger on the road. If you are to give a place in your house to a group of flood victims and you have to make a choice between your relatives and others, you're more likely to make room for your blood. Such patterns or preferences are quite natural in the animal kingdom but absent in the pro-English sentiment rising from the anti-Hindi sentiment. They prefer to exalt a foreign language than one of our own. This is an anomaly and therefore raises a flag that the motive for anti-Hindi sentiment is not fairness, but something else.
The anti-Hindi sentiment reminds me of the Bhāratīya princely states whose differences made Bhārata weak and an easy target for the invaders to conquer and ruled. The idea of letting a foreigner conquer us than allowing one of our own to take a more prominent place among us, defend us and maintain our identity is a recipe to destruction. And the signs are evident — citizens are getting less proficient in their mother tongues and more proficient in English. While the latter is not a problem, the former is. Moreover, making one of our own languages our link language is a validation of our unity and cultural belongingness, that we are able to set aside our differences and choose one among us.
The other argument is that many Bhāratīyar do not understand Hindi but they understand English, therefore English must be preferred over Hindi. Assuming that this observation is true, the logic of the argument fails because the consequences of anti-Hindi policies is being used as the problem which the continuation of the anti-Hindi policies will mitigate. To simplify it, the reason why most Bhāratīyar do not know Hindi in the first place is because they were not taught the language, and the reason why many know English is because they were taught the language. So the solution is simple — teach them Hindi and the problem of not knowing Hindi vanishes.
The third argument is the imposition of Hindi in school curriculum — which is laughable when you recall as to which subjects taught in schools are not imposed. I do not remember any teachers, principals, parents or education ministers seeking my permission to teach me English, science, maths, history, social science and other subjects. They were all imposed on me and other students. All subjects taught in schools are in principle imposed by an authority. So if imposition is the reason behind the anti-Hindi sentiment, we should see equally unpleasant sentiments towards other languages too — which we do not. This drives me to conclude that the argument of imposition is not the reason for the anti-Hindi sentiment, but a justification of it. True reason is something else.
If it is countered that Hindi is said to be imposed not because students are not asked for permission, but because people do not like it, here again, the argument fails logic because the reason why people have difficulty in accepting is because of an anti-Hindi sentiment in the first place. Once again, the consequence of a policy is being used as a problem that the policy will resolve. Utter stupidity.
The fourth argument is that mother tongue must be preserved. Indeed yes, and I have always given the first priority to mother tongues. But a national link language will not kill anyone's mother tongue. A link language by definition does not mean that two Malayāḷi or two Tamillians or two Kannadigas will speak with each other in the link language, but two individuals speaking different mother tongues will speak to each other in the link language. Mother tongue will be preserved and will remain as the primary language for each linguistic culture. Hindi or Sanskrit is not proposed to replace mother tongues, but English.
Then there are arguments such as that we are a diverse nation. Yes we are! And that's why we need a national link language to communicate between the diverse linguistic cultures. In some daises such as the parliament, we have the privilege of translators allowing the members to speak in their mother tongues, inciting a atmosphere of true diversity. However, one does not have this privilege in every day lives. Had a Tamillian been in Punjab for a long time, either studying, working or settled in the state, it can be expected that the Tamillian learns Punjabi, and vice versa. People living bordering areas of two states naturally develop command in both languages, and therefore can communicate between them in either one language. But in every other case, such as while travelling, debates, business meetings, paperwork of central government or the supreme court, there is a need for a national link language that is Indic in nature.
The anti-Hindi sentiments do not stand the test and treatment of logic. The true reason behind the absence of a Bhāratīya language as the national link language is politics. May every Bhāratīya soul of whatever culture and religion it belongs to, use its common sense to wade off political narratives from social issues, whichever party does that, and form a sensible conclusion.
To sum it up, the mother tongue must be the first language of a citizen followed by a national link language, which should be Sanskrit, but since Sanskrit literacy is low, should be a closer language like Hindi. English comes as a global link language.
Script
Since both Sanskrit and Hindi are languages without a script, there is a need for a national script, and Devanagiri is the most eligible one. A national script also serves the additional benefit of conveying many elements such as the name of a place or numbers to everyone seamlessly.
Some mistake Devanagiri to be Hindi. When the name Tiruvanantapuraṁ is written in Devanagiri as तिरुवनन्तपुरम, you are not reading Hindi but a Malayāḷam word written in Devanagiri. When you see number १५८, you are reading Hindi but the number 158 in Devanagiri.
Devanagiri, unfortunately does not cover all the sounds of Bhāratīya languages — such as റ and ഴ of the Malayāḷam language. So, in the interest of serving all languages of our nation, Devanagiri script must be improved by a selected authoritative committee to expand the alphabets to include such sounds.