It began with a study one of them did on a dolphin, who had been trained to recognize a particular high-pitched tone.

首先，他们中的一个人对海豚做了一项研究，训练它识别一种特殊的高音。

youdao

We should use a moderate tone of voice, and avoid speaking in a sharp, high-pitched voice, which gives people the feeling that we are showing off or arguing.

尤其要避免用尖锐拔高的音调讲话，令人感觉你在卖弄本事或争论。

youdao

Be careful about the tone of your voice. Keep it evenly moderated and avoid getting a high-pitched, whiny or tearful tone.

对自己的语调要十分小心。使它保持均匀地…避免高嗓门、牢骚或哭腔。

youdao

But when they downloaded the Larry The Bird character (which is also an app created by Outfit7), which has a high-pitched tone, they could understand what she was saying.

FORBES: Apple's Talking Santa

While the message began its voyage to the cosmos--a 24, 000 year trip to M-13, a cluster of stars in the constellation Hercules, to be exact--visiting dignitaries listened over a loudspeaker while each bit played as a short, high-pitched tone.

FORBES: How To Talk To Aliens