Oryan77
Adventurer
The last seems pretty reasonable
"We can excuse the fact that you slaughtered two Yugoloths before you realized where you were, Outsider. But you pronounced the name of our fair city 'Sijil,' not 'Sigil,' and there can be no excuse for that! - Her Honor Rastina Tollin of the Guvners (Sigil and Beyond page 4 of the Planescape Campaign Setting boxset)
Except that in the Planescape setting it explicitly states that the name of the city is pronounced "sig-ill." Mispronouncing it is one way the locals identify the noobs.![]()
I had a player once that kept purposely pronouncing it sijil because he was a prime and he thought it was more appropriate to do that to identify that he's a clueless. His character kept insisting that that is the way to say it.

It's interesting to see that a lot of people trip over the same words that I do. It's also interesting to see words that people mispronounce that I never thought would give someone trouble. Funny.