In "Wolfy Mountain," it is revealed that the Ninjalinos have names.
In "Master Fang's Secret," it is revealed by Night Ninja that their gibberish is actually a language called Ninjalino-ese.
The Ninjalinos are the fourth characters to not have English as their primary language.
The first three characters are the Pyjamasques and the rest of the characters in the picture book series (in which they only speak French), and the moths.
As of the Season 4 episode "Teeny Weeny Returns," Teeny Weeny decided to betray Night Ninja in order to make up for his past actions as a ninja, becoming one of the heroes.
So far, the Ninjalinos have appeared four times without Night Ninja.