Dug: My master made me this collar. He is a good and smart master and he made me this collar so that I can talk. Squirrel!.My master is good and smart.
Carl: It's not possible!
Dug: It is, because my master is smart.
Carl: Russell, if you don't get up, the tigers will eat you.
Russell: There aren't any tigers in South America. Zoology.
Beta: Treats. I smell treats. I like treats.
Dug: My name is Dug. I have just met you and I love you.
Chosen answer: Carl and Ellie have two dramatically different personalities. Carl is more conservative, more reserved, a tender heart covered by a tough exterior which Ellie is able to break through, but which seems to recalcify after she dies. Ellie, on the other hand, is the sweet free spirit, rambunctious and adventurous. Throughout the film, each one conforms to the other until they ultimately blend into one beautiful unit. I think the makers of the film were trying to show that their respective personalities were a product of their upbringing, and reflected in the reactions of their families - hers larger, more fun, and more "hick" (we hear gunshots, for Pete's sake), and his more reserved, formal and patrician.
Michael Albert