Letter written on 19 Jan 1960
From 1957 to 1963, Osho wrote many letters to Babulal Ji Deriya, of Babai (MP), India. The wiki has images of thirteen, believed for now to be all of them. Most are written on postcards. This one was written on an Inland Letter form. See Deriya Ji's page or Osho's manuscript letters for links to all these letters.
For the Post Office, Osho used his full name as above. In addressing him personally, he wrote "Poojya Deriya Ji" or "Shraddheya Deriya Ji" (venerable, honoured), only later using the more familiar "Priya Deriya Ji" (dear, beloved), but all following his sometime custom of addressing male friends by their last names. See also Lashkariji, Punglia Ji, etc.
This letter is dated 19th January 1960 and sent from Jabalpur. An English translation was published in Sw Ageh Bharti's book Beloved Osho, and likely the Hindi original version was published previously in one of Ageh's Hindi books. It is said also to be in line to be published eventually in a larger edition of Prem Ke Swar (प्रेम के स्वर) (as letter #62), though this development appears not to be fast-tracked. In the letter, Osho ponders an invitation to speak but is in a truth-cannot-be-put-into-words mood and will participate only in a limited way if pressed.