[Nyororin]

Here is my answer. I`ve lived in Japan for over 10 years, and went to an all girls high school here. Whether that is good enough for you, I have no idea.

I think that in order to answer this, you have to look at not just higher pitches but also lower. Let`s say we have 3 general pitches - normal, low, and high.

Normal is neutral - the natural voice pitch. It carries no "meaning". People COULD use their normal pitch... However -
Low is a "private" and often looked at as "seductive" voice.
High is happy and energetic.

Better to err on the side of caution and sound more happy and energetic than seductive, right? So the tone goes up. This is true for both women and men, but women are more critical of the lower tone.

Among Japanese women, the higher pitch is a demonstration of innocence. You won`t see anyone actually saying that the pitch is representing that, but if you ask what a lower pitch voice in a woman means they will have no trouble telling you that it sounds "naughty" in a sexual way, or like a seductress.

The thing is, no one thinks consciously about this. It isn`t as if girls go around thinking "I need to sound innocent!". It`s more that girls are supposed to be innocent - no one wants to seem the opposite - so it becomes a natural part of life. The raised pitch is normal - a natural or lowered pitch is NOT.

Speaking in a high pitch to someone`s boyfriend or husband is normal - but if you were to drop your voice it becomes "private". Sort of a way of letting down your guard.

With men, the lower voice is usually looked at as "sexy" - which doesn`t carry the negative connotations of "seductive". But still, in polite situations and the like it is better to err on the "happy" side, so men will raise their pitch.

A lot of entertainers will overdo it because of the connotations of "happy" and "energetic" that come with a higher pitched voice. Pitch naturally rises when you are excited - as an entertainer it`s better to sound like you`re excited about what you`re doing than not.