Continuity mistake: When Chief Wiggum orders his men to open fire on the dome, and the bullets ricochet back, the officer standing farthest from Wiggum is wearing blue gloves on both hands in the overhead side shot, and the other officers are not wearing gloves. However, in the shot facing them, the officer kneeling farthest from Wiggum is the one wearing blue gloves, and now all the others are barehanded. (00:28:35)
Continuity mistake: When Maggie gets out the dome, Marge runs to get Homer. They run outside in a straight 12 o'clock direction. Yet as Homer says "This dome can play tricks on you", they are suddenly several steps to the right of the door instead of being directly behind it. (00:30:00)
Continuity mistake: When Marge sits on the back porch swing knitting 'dome sweet dome' and sees Maggie outside the dome, she runs inside to get Homer. The back door is right behind her and it's a solid door, with the round window missing, though the window does reappear. (00:30:35)
Continuity mistake: When Marge and Homer are watching the news about the silo found in the lake, the TV sits on the dresser in front of their bed. The TV has vanished when Lisa runs into the bedroom, and when Marge tells Homer to go out, face the mob and apologize for what he did, the rest of the wall is visible, sans TV. (00:30:40)
Continuity mistake: Eddie and Lou are at the lake making notes about the Pig Crap Silo. The next shot is of the town approaching the Simpson house and Eddie and Lou can be seen in the mob. (00:30:50)
Continuity mistake: After Marge has brought Homer to see Maggie outside the dome, and then he thinks he's out of the dome, when he runs back into the house the water spigot attached to the house has vanished. (00:30:50)
Continuity mistake: When the silo is pulled out of the lake, Eddie is writing in a notepad. However as the silo turns round he has his arms crossed. (00:30:50)
Continuity mistake: When Marge brings Homer to see Maggie outside the dome, but she's not there, he soon starts cheering and in the dome's reflection he raises his right arm which means it's his left arm that is actually raised, but when it cuts to Marge and Homer (in the view from outside the dome) it's his right arm that's raised in a cheer. (00:31:05)
Continuity mistake: When Maggie does her disappearing act through the sinkhole, and Marge rushes to get Homer, the wooden porch swing is directly in front of the window, with its top beam as high as the top of the window. When Homer says, "This dome can play tricks on you," note the door and window behind Marge, because the swing is now gone. (00:31:10)
Continuity mistake: After Homer taunts the angry mob about not knowing where he lives, the mob gathers in front of his house, and in the shot of Homer and Marge in the bedroom note the light switch on the wall and the items on the dressing table, but in the next shot as Lisa and Bart run into the room the items on the table have vanished and the light switch is gone. (00:31:30)
Continuity mistake: When Homer falls onto the barbecue during the failed escape, there is a lower window at the corner of his house, which didn't exist in the exterior shot of the house, just before we see Homer and Marge watching the news about the silo being discovered. (00:31:50 - 00:34:50)
Continuity mistake: When Marge and Homer are watching the news about the silo being found, the '6' on Kent Brockman's microphone keeps getting smaller, the color of his belt buckle changes and the landscape in the background changes. (00:32:00)
Continuity mistake: When the angry mob breaks down the front door of the house, the door knob is on the right side of the fallen door, at Chief Wiggum's feet. However, when Maggie breaks her bottle and thrusts it forward, in the next shot as Mr. Teeny turns and runs away, the doorknob is on the left side of the door, at Bumblebee Man's feet. (00:32:20)
Continuity mistake: After Homer and Marge watch the news about the silo found in the lake, when Homer walks to the window we see that there are two blue panel drapes with tiebacks on the left and right side of the sliding window. However, when Homer shouts at the mob in the exterior shot, there is also another blue panel hanging down at the center of the sliding window, and the side panels are hanging straight down, without the two tiebacks. (00:32:30)
Continuity mistake: After the news broadcast about the silo being discovered in the lake, in the first shot of Homer nailing the bedroom door shut, the blue panel drapes and valance have become beige (seen right behind Lisa and Bart). (00:32:30)
Continuity mistake: When the mob are invading, Lisa sees Colin in the crowd with a bouquet of flowers and nothing else. Later on after the house is destroyed, he suddenly has a guitar with him despite not having it with him a few minutes earlier. (00:32:30)
Continuity mistake: During the scene with the angry mob, knobs on the bedroom's wall cabinets keep switching between being on the left or right sides of the cabinet doors (which would also change the direction those doors open). (00:32:50)
Continuity mistake: When the mob approaches Homer's house, it is undamaged. However, a few seconds later when everyone is out of the house, it is suddenly ablaze, and it is clear that it's falling apart. But when the sink hole sucks the house in a few minutes later it is undamaged, and no evidence of a fire is visible. (00:32:50)
Continuity mistake: When Bart looks out the bedroom window, and Ned tells Bart that he and his family should crawl out on the plank to his house, the pair of blue panel drapes and tiebacks have turned yellow. (00:33:00)
Continuity mistake: After Homer nailed the bedroom door shut and then mimicked the sound of a chainsaw, when the hands of the angry mob push through the holes again, we see Marge and Lisa sitting at the edge of the bed where the bed's tall footboard should be. The footboard is back when Spider Pig pushes the plank off the windowsill. (00:33:05)
Answer: I believe the joke is supposed to be that the way Texans speak is a language all its own.
Damian Torres