Sesquipedalian
An adjective denoting the use of long words.
Loquaciousness
Being talkative and/or being unable to just shut up.
Bombastic
Similar to the above but also suggests bragging, arrogance or just being unnecessarily wordy for the sake of showing off (yes, I realise the irony).
Verbose
Taking too long to say something, doesn’t carry the same negative connotations as bombastic, can imply that the something being said wasn’t so interesting.
Grandiloquent
A polite insult, used to suggest somebody is absurdly long-winded, not to suggest that they’re talking for an implausible amount of time, just that the amount of time taken to say something has itself become amusing.
Paraskavedekatriaphobia
Fear of Friday the 13th, also called idiocy.
Hippopotomonstrosesquipedaliophobia
The fear, of long words... yeah.
Edit: Verified, it's true
Coincidentally there is a masochistic PCP with hippopotomonstrosesquippedaliophobia (fear of long words) curled up in an alleyway across the street. He has been whispering “Antidisestablishmentarianism” to himself over and over for two days now, experiencing up to one orgasm every three hours as a result of the pain.
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LOL