Even though is hard to establish the exact [size of the English lexicon](http://www.oxforddictionaries.com/words/how-many-words-are-there-in-the-english-language), this is probably not the case. The main reason is that Esperanto is a relatively young language, while English is much older and has absorbed influences from French (from Old French after the [Norman Conquest](https://en.wikipedia.org/wiki/Norman_conquest_of_England), but also from more recent varieties of French), Latin, Greek, Dutch, Italian, and from several languages spoken in the former colonies. There have been claims about the English about [the English language having a million words](http://www.languagemonitor.com/number-of-words/number-of-words-in-the-english-language-1008879/).

For comparison, this [Q&A document from Esperanto USA](http://esperanto-usa.org/posters/QA.pdf) says that the *Plena Ilustrita Vortaro* contains 16,000 root words and that Esperanto's word formation techniques allow this number to be expanded to around 160,000 words. However, I don't know how you would come up with Esperanto translations for [malapropism](https://english.stackexchange.com/a/344202/163363) or [sciolist](https://english.stackexchange.com/a/344265/163363), though I certainly hope so.