Wait, what? I can't remember when it was pronounced in the movies and I also (mentally) pronounce it as 'Smog.' It has never come up in IRL conversation so I don't know how it's actually pronounced.
Does anyone have a clip/timestamp on a video to show how it's actually pronounced? It's been a long time since I've seen the movies.
It's /smawg/, it should sort of feel like the name doesn't fit me your mouth properly, English phonotactics doesn't allow for gliding from W to G without a vowel in between.