What does a spectrogram display?

A spectrogram is a visual representation of the spectrum of frequencies in a sound as it varies with time. It typically displays three key elements: time on the horizontal axis, frequency on the vertical axis, and intensity or amplitude represented by the color or shading of the spectrogram. This allows observers to see how the frequency components of a sound change over time, making it an invaluable tool for analyzing speech and other complex sounds.

While the formants of vowels can be identified on a spectrogram, the spectrogram as a whole encompasses much more than just these aspects of vowel sounds, as it represents all frequencies over time in a given sound. Thus, the correct choice highlights the comprehensive nature of what a spectrogram displays, emphasizing its role in evaluating the frequency spectrum across time.