Why do formant frequencies of adult men tend to be lower than those of children?

The correct answer addresses the anatomical and physiological differences between adult men and children, specifically focusing on the size of the vocal tract. Adult men generally possess a larger vocal tract compared to children, which directly influences the formant frequencies produced during speech.

Formants are resonant frequencies of the vocal tract, and their characteristics depend significantly on the length and shape of the vocal tract. A larger vocal tract, as seen in adult men, leads to lower resonating frequencies, resulting in lower formants. In contrast, children have smaller vocal tracts, leading to higher formant frequencies. This acoustic principle highlights how physical dimensions play a crucial role in speech sound production.

Other options may reference different factors such as vocal cord thickness or age-related changes, but they do not as directly explain the difference in formant frequencies as the size of the vocal tract does. Breathing techniques influence voice production but are less relevant to the specific frequency characteristics we associate with the anatomical differences between adults and children.