Short form of extra modest expression I recently came across an example of someone saying '' rather than '' about 18 seconds into this video: Under what circumstances should people use the short form of an extra modest expression? Or does it have something to do with the fact that the speaker is a child?

A simple answer is, yes it is used as since the speaker is a child. It looks like the girl speaks without / endings, and that is why is used.

Probably a confusing thing is that is certainly , but to mean _the favor in return_ , is the only possible form.

You can see many samples mentioned in the definition of are prefixed by , and those cannot be omitted.

In other words, in exists because of vocabulary, and not (very much) of . I cannot really think of other phrases (usable by a child) to mean _return the favor_ than . (Maybe is possible, but again cannot be omitted)