Continuity mistake: A shot after Larry is bitten in the nose by Dexter, he drops the instruction manual on the ground in front of the metal bars. However, when Larry gets angry at Dexter a shot later, the instructions appear in Larry's hand. He never bent down to pick them up.
Continuity mistake: After the caveman jumps out of the window, while Dexter is holding the keys, the key with a rubber protection around is in front of the remaining keys or behind them, depending on angle.
Continuity mistake: After the T-Rex throws the bone at Larry, a stack of white papers suddenly appears under the yellow notepad by Larry's foot.
Continuity mistake: Before Cecil escapes, amount of snow on the side of the van decreases between the first and second shot, from the Indian and the Roman's POV.
Continuity mistake: When the caveman sees the open window, after he sees the homeless on the street, the amount of foam on his head and its position changes completely.
Continuity mistake: When Cecil hops in the van, the snow on the windshield is suddenly gone.
Continuity mistake: After the T-rex tosses the bone and puts his nose next to Larry's face, Larry swaps from backing away from Rex, to kneeling towards him between one frame and another.
Continuity mistake: During the T-rex attack, when Larry is phoning Cecil, the phone cord swaps from wobbly to straight depending on the angle.
Continuity mistake: After being given the job, Larry makes a phone call and his watch moves further up his sleeve towards the cuff between shots.
Continuity mistake: When Larry "vanishes" the handkerchief and some is left on his thumb, after he says "vanishing" and holds the palms of his hands outward toward the Huns, we see a shot of the Huns, and we see Larry starting to turn his hands back around. However, a second later, when he says "into thin air", he is still holding the palms of his hands outward toward the Huns like before.
Answer: Columbus is speaking Italian. The first night, when Larry asks him about the lions, he says "Go find the lion somewhere else" and then "tourist!" The second night, when they're chased by the animals, he says "Young man, do your job well, take care of the beasts" and when he sees that the window's open, "Kid, what do you say, shall we close the windows?" The last night, when Columbus is guiding the Neanderthals, he says "Fellow Neanderthals, with me!" and to the night guard "It's over!"