The letters "l" and "d" and "l" and "d" sound very similar. However, it is important to distinguish the difference between words with "ld" and "lt". Sometimes the word does not even exist, and sometimes it is a different form of that word!
Rufio uses adjectives to insult Peter Pan at the dinner table in front of the other Lost Boys. After some time, Peter Pan stands up for himself and replies with his own, creative insults. This is an excellent example of how powerful adjectives can be in language.