enormous
The longest word starting with E is Electroencephalographically.
Acetylcholinesterase is a 20 letter word. It is a chemical compound.
Floccinaucinihilipilification is the longest word starting with F; it means the act of estimating something as worthless.
Pneumonoultramicroscopicsilicovolcanoconiosis (also happens to be the longest word in the English language)
Extraterritoriality is the longest word in the English language beginning with "ex."
Methionylthreonylthreonylglutaminylalanyl...isoleucine. It has 189819 letters and the longest word in the world.
That's an interesting question. I dont' know for sure, but the longest one I can think of right now is Electric. Hope I helped!
Erectile
The longest word starting with a "P" is pneumonoultramicroscopicsilicovolcanoconiosis, which has 45 letters and is in the Guinness Book of Records. It was, however, coined for the specific purpose of becoming the longest word, and is not a specifically recognized form of silicosis.
Although they don't have the /e:/ sound, the longest words listed are countercountermeasures, interchangeabilities, and tenderheartednesses. The longest word with the /e:/ sound has 18 letters unreasonablenesses.
forethoughtfulness
Immunoelectrophoresis-- 21 letters