Acoustic effects of loud speech across vowels and speakers

Abstract

Although loud speech is widely agreed mainly to involve increased respiratory driving support leading to greater acoustic intensity, past work suggests that speakers may make laryngeal and supralaryngeal adjustments as well. For example, previous studies suggest that loud speech is accompanied by greater jaw displacements as well as formant frequency variation, especially in the form of higher first formants. Acoustic studies have generally not sampled widely across the vowel space, however. This study assessed how formants, f0, duration, and intensity varied across conversational and loud conditions, with a particular focus on formant frequencies. Eleven German-speaking women performed three speaking tasks: Reading, answering questions, and recounting a recipe. Target words included a range of high, low, tense, and lax vowels. Loudness variation was elicited naturalistically via changing interlocutor distance. Initial results from the reading and question-answer tasks suggest that formant frequencies vary on average in louder speech, particularly for F1, but the effects are speaker-dependent and may also differ between high vs. low and tense vs. lax vowels. These acoustic data will ultimately be combined with simultaneously recorded data on intraoral pressure, vocal-fold contact, and breathing kinematics to assess the range of speakers' strategies for achieving louder speech.