translation.en: A spectrogram is a graphic illustration of sound with time from left to right across the page -- 15 seconds in this case is represented — and frequency from the bottom of the page to the top, lowest to highest.
translation.zh: 声谱图是以图像形式表现声音 从左到右是时间 这个页面有 15 秒 从底部到顶部是频率 由最低到最高