Effing prosody.

I used to know a lot about the prosody of what linguists refer to as expletive infix, but no matter where you put the infix, ridiculous sounds... ridiculous.

Absolutely is two trochees -- AB so LUTE ly -- so expletive infix (also a trochee) slides nicely right in there, but ridiculous is an iamb and two unstressed syllables -- ri DI cu lous.

I think expletive infix works better if you put it in after an unstressed syllable, so maybe the XKCD person's "awkward" way of saying it is the best one there is, but they're right about the awkwardness of that last syllable.

No word yet from Language Log, usually the foremost authority in webcomic linguistics.