Sreekar Saha sent in this sign and expressed puzzlement over the English translation:
Before trying to figure out precisely what the Bengali says, I'd like to point out that, in essence, what the English says very politely is "Do not loiter" (not as strong as "No trespassing"). Telling people not to do nothing is not the same as telling them to do something.
Now, to tackle the Bengali. First of all, I was surprised by the variety of transliterations (not to mention translations) that I received from native Bengali speakers and Indologists. Perhaps this is due to the fact that there is no normative or standard transliteration for Bengali in English (I really don't know if there is or isn't). But I suspect that the differences in some cases may be due to dialectal and even idiolectal variation. For example, whether ফ is "f" or "ph".
I will give several of the transliterations for the sake of comparison. Then relying on charts from Omniglot and Wikipedia, you can follow along for yourself if you wish to do so (fortunately, the lettering on the sign is clear and distinct).
1. BINAA PRAYOJANE GHURAAPHERAA KARBEN NAA
(NOTE : AA stands for LONG A)
2. vinā prayojane ghurāpherā karven nā
3. bina prayojane ghurafera karben na
4. bina proyojone ghuraphera korben na
5. bina proyojone ghurafera korben na
6. bina proyojone ghurafera karben na
Here are some of the translations I received from the experts:
1. Do not loiter about if you have no business/nothing to do.
2. Don't wander around without purpose.
3. Do not hang around / wander without reason.
4. Without necessity do not hang out.
5. Without it being necessary, don't loiter / run around 'n stuff [here].
Leopold Eisenlohr, who provided the fifth translation, also offered these interesting notes:
Bina = without (probably same in Nepali? same in Hindi), proyojone= necessary, korben na = "you will not do" as a polite imperative, and ghurafera is more interesting. Ghura means to go around, spin around, as you would say for somebody running errands all over the neighborhood or something. In Bengali there is this lovely device of repeating the word with a different initial consonant, which gives the meaning "and stuff." Shower is chaan, so chaan-taan is "showering and doing all the other bathroom stuff like shaving etc;" packing-tacking means "packing and all the other stuff you do when you're getting ready to go on a trip. Usually the repeated word comes with a T, but I guess ghurafera just sounds better than ghura-tura.
There's something about this sign (both in the English and in the Bengali) that leaves me pondering all sorts of existential issues. I have had the same sort of feeling after watching many a Satyajit Ray film, listening to Rani Shankar play an evocative raga, or reading a poem by Rabindranath Tagore.
[Thanks to George Cardona, Leopold Eisenlohr, Prasenjit Dey, Tansen Sen, Saroj Kumar Chaudhuri, Sunny Jhutti / Singh, Abdullah Mahmud, Philip Lutgendorf, and Fred Smith]