The inspiration for Newspeak is Basic English, which is much like Esperanto but with English words (at least it's described as such — I'm not actually very familiar with Basic English myself). Constructed languages had some avid supporters back in the early 20th century, looking to make some constructed language the international language. Though I don't know much about Basic English, the unique looks of Newspeak definitely come, directly or indirectly, from Esperanto's ideas for keeping the vocabulary small and simple. To illustrate, in Esperanto the word for "good" is "bona", "bad" is "malbona" ("ungood"), and "to improve" is "plibonigi" ("to moregoodify").
I was wondering more about why he put newspeak in 1984 as a way for party to controll people minds and eliminate "though crimes". I do not know history of Basic English and Esperanto but it seems very improbable that their creators were aiming at the same goals as Ministry of Truth.
