What happens when the tongue is raised and fronted in speech production?

When the tongue is raised and fronted during speech production, it plays a significant role in modifying the resonance characteristics of the vocal tract, specifically affecting the formants, which are the resonant frequencies of the vocal tract. The correct choice indicates that the oral cavity is made smaller, which typically lowers the first formant frequency (F1) and raises the second formant frequency (F2).

Raising and fronting the tongue reduces the space in the oral cavity while increasing the overall cross-sectional area of the resonant space behind it (in the pharyngeal area). This change in tongue position results in a higher frequency sound being produced, as the smaller oral cavity causes lower resonances to shift downwards (lower F1) and higher resonances to shift upwards (higher F2). These adjustments define the acoustic characteristics of different vowel sounds in various languages, as vowel quality is heavily dependent on tongue position during articulation.

In contrast, the other options do not reflect the physiological and acoustic outcomes associated with raising and fronting the tongue during speech. For example, the oral cavity is not simply enlarged or made muffled; rather, it's the nuanced changes in size and shape that lead to fundamental shifts in the formant frequencies, specifically F1