Which of the following factors can affect formant frequencies during speech production?

Formant frequencies, which are crucial for characterizing vowel sounds and some consonants in speech, can be influenced by a variety of factors related to speech production. Articulator movements play a significant role as they alter the shape and size of the vocal tract. For example, moving the tongue forward or backward changes the resonant frequencies, resulting in different formant patterns.

Sound pressure level also impacts formant frequencies; as the amplitude of the speech sound changes, the resonance characteristics of the vocal tract may shift, leading to variations in perceived pitch and vowel quality.

Aging affects the morphology and function of the vocal tract and associated articulators. As individuals age, physiological changes can lead to differences in formant frequency characteristics, influencing how sounds are produced and perceived.

Considering that all the listed factors—articulator movements, sound pressure level, and aging—can affect formant frequencies, the most comprehensive answer is that all of these factors contribute to variations in formant frequencies during speech production. This underscores the complexity of speech and the importance of considering multiple influences in speech science.