Well, this doesn't necessarily apply to all of India - I was born in India and lived there for several years, and not once did I hear someone say "Do not speak this".
I think it'd be better for everyone learning Hindi from across the world to have a grammatically correct sentence.
"Do not say this.' is most likely the intended translation. Traditionally, this is how it is said in Hindi. We can use other words for "speak" but I don't think it would have the accustomed impact:
कहना say, tell, state, report, express, put to बोलना speak, say, talk, tell, accost, sound बात करना tell, say वर्णन करना describe, depict, delineate, characterize, represent, say विचार स्थिर करना say कल्पना करना imagine, envision, speculate, figure, fancy, say
Thank you! So it seems that the English translation that would have the closest meaning would actually be, "Don't say that". In English I don't think it would be usual to say, "Don't say this" if someone was saying something you weren't happy about. It would be "Don't say that!"
It’s really frustrating to have to deal with less than ideal English translations. I’ve been working as a translator for the past 22 years. While I do understand the intricacies and singularities of each and every languages, being stuck on a level because of improper use of the English language is rather frustrating. While I do also understand about regional uses and expressions, being “forced” to reply using “do not speak this” makes me question the whole proofreading part of this program.
We do not say it in my English, nor apparently in yours. I assume by "international English," you mean what is accepted in the United States and United Kingdom (and Australia and Canada, though their smaller populations, without the historic prestige of British English, have little influence on it). English, though, is spoken natively by people all over the world, particularly Africa, Asia, and the Caribbean. While the English spoken there might be strange to me as an American, I do not see why what I speak should be the only acceptable answer.
That said, what is acceptable to me ("Do not say this") should certainly be an accepted answer. Indeed, while "speak" is a problem, I even have a hard time thinking of a situation in which I would say "this" rather than "that." Even if I were pointing to something in a text, I would probably say "Do not say that" rather than "this."
That is a uniquely American attitude, which does not make it correct, for it is not reflected around the world.
The British consider their form of English to be the standard, as do a high percentage of countries around the world, although knowing American English is quite desirable because of its economic impact worldwide.
I am also taking a formal Arabic course and it is known and universally by Arabic speakers that there is a "Standard Arabic", in contrast to the many regional dialects in the many other Arabic speaking countries. That does not mean they are incorrect, just not the Standard.
Spanish is similar - there is Standard Spanish (see Wikipedia), or you can learn various forms of Spanish spoken in other countries.
In Chinese the standard is Mandarin, although it is generally understood that Cantonese is most likely the original dialect. There is no value judgment on the other dialects, they just are other dialects.
I think the point is bring missed. The Hindi sentence is grammatically sound when speaking it in Hindi. We will not find the exact translation in English from any language. In order to speak English properly we learn the language of English. To speak Hindi properly, we learn Hindi.
However, if the English "translation" makes no sense to English speakers, then they are NOT learning Hindi. They don't know what the sentence means, so don't know when it might be appropriate to say it in Hindi.
There are a few examples like this scattered through the Hindi course. They are not helpful to this type of learning. If this was a class where we could ask the instructor for more information about the situation in which such a sentence would be uttered, we could get a better understanding and a deeper knowledge of Hindi. But in a computer-based, one sentence at a time, no explanation, learning activity, sentences which cannot be translated exactly have no place. They don't teach anything.
I agree that Duolingo should have both the literal translation and then the accepted English translation. However, please bear in mind it is a no-charge program and therefore the expectation of having live instructions may not be reasonable. There are several paid-for programs online like Verbling and Rosetta Stone where live tutoring is available.
It is not correct English. Normally you "tell" someone something. So your sentence would need a person that was not being told. So, "Do not tell anyone this", might work, although "Don't tell anyone about this" sounds more natural.
However, from the discussion above, the meaning of the Duolingo sentence seems to be more, "Don't say that!".
Here is a page with some of the differences between "say" and "tell". http://www.learnersdictionary.com/qa/what-is-the-difference-between-tell-and-say