On Twitter I asked Lord British himself how several Ultima VI names should be pronounced, and he responded!
How did YOU pronounce these names when you played the first time? I think me and my brother said Shuh-MEE-no, Eye-lo, Dooper, and Jan-uh. If only every game copy came with FM-Towns, then we could have heard them right away!
The thing is, Dupre and Iolo will sound out their names in text if you ask them their name - but why would you since they are in your party at the start of the game, and their names are clearly visible in the party list? Shamino, however, says "Shamino Sallé Dacil " and doesn't pronounce it for you - unless you have the FM Towns version of Ultima with full voice acting. Then he says "SHAM-in-oh Sah-YAY Dah-SEEL."
Here's the original fb UDIC post.