american english - Intention of rising pitches

I have been wondering about the rising pitch used in almost every sentence, by especially young Americans.

1. What is the purpose/intention of rising pitch except in questions?


2. Is it friendly and polite, or condescending?


3. Is it proper to be used in presentation and teaching and other professional occasions?

For example: In this video, starting around 0:40, when Amy Chua introduced herself.

Answer

What you're talking about is known to linguists as the High rising terminal (HRT), and referred to informally as uptalk. This is a relatively recent phenomenon in spoken American English, and its origins are unclear. What is clear is that it doesn't signal a question, and is perceived by many people to be sub-standard and irritating. For that reason you should avoid it if possible in formal settings.

For more information, here is a very long and informative Language Log post about HRT, including a variety of links to other sources. I quote a few paragraphs from near the end which elaborates somewhat on the possible intent and usage of HRT:

As I understand it, uptalk is often (intended and understood) as an invitation for the interlocutor at least to signal attention and perhaps also to assent.

The key thing is that "uptalk" is not a signaling a question, in the literal sense of a request for information about the truth of the proposition being presented; nor does it (usually) mean that someone with low self-confidence is making a plea for reassurance. Rather, the studies suggest that it's usually someone who feels in control of the interaction and is inviting a response, as evidence that the interlocutor is going along.

But there are quite a few reasons for final rises in (most forms of) English: the intitial if-clause of a conditional or the first option of an exclusive disjunction is often rising; lists may be presented with rises on their non-final members; and of course yes-no questions are stereotypically performed with final rises.

Some dialects apparently use final rises as the default option, or at least much more often than speakers of other dialects expect. This is apparently true of Belfast English, for example -- and something similar has apparently been happening with the world-wide spread of uptalk over the past couple of decades, at least in the sense that some people have come to use final rises much more often. It's possible that the thin edge of the uptalk wedge, so to speak, has been the "are you with me?" rise. Pretty much all English speakers use this sometimes, or at least can do so if they choose to. But if someone chooses to do this almost all the time, then its force fades with repetition, and perhaps in some cases becomes almost totally bleached out.