Phonetics and Acoustic Cues Overview

Understanding Phonetics and Voice Onset Time

• Overview of Phonetics

• Discusses how certain languages and voices incorporate aspiration and other features.

• Aspiration refers to the burst of air that sometimes accompanies consonants in speech.

• Aspiration in Speech Sounds

• Clear aspiration observed in some instances, while others lack it.

• The aspiration occurs after a burst and before the onset of formants (the dark bands in spectrograms).

• Voiced consonants show no voice bars in specific examples, indicating continuous voicing through the vowel.

• Interpreting Speech through Acoustic Cues

• Our brains utilize a variety of acoustic cues to differentiate between speech sounds.

  • Important cues include ability to discern whether a consonant is voiced or voiceless, the energy levels of the sound (low, high, mid), and the relative lengths of preceding vowels.
  • Example: “pub” vs “puh” - vowels preceding voiceless consonants are shorter.

• Voice Onset Time (VOT)

• VOT is defined as the time (in milliseconds) from the release of a stop consonant to the onset of vocal cord vibration for the following vowel.

• Distinct VOT patterns exist based on the place of articulation:

  • Bilabials - falling transitions.
  • Alveolars - nearly straight transitions.
  • Velars - could be rising.

• Glottal Stops

• Occur via a rapid closure of the vocal folds leading to a stoppage of voicing.

• Unique as they cannot be voiced and have no voiceless pairs.

• Example: Diftic closure of vocal folds leading to creation of a glottal stop.

• Production of Stops

• Articulators can stop airflow leading to voiced or voiceless sounds.

• For bilabials: lips come together to create a stop, while vocal fold activity can create voiced stops (e.g., /b/, /d/).

• Glottal stops involve stopping airflow at vocal fold level making them inherently voiceless.

• Key Concepts to Remember

• Understanding vocal fold involvement helps distinguish between voiced and voiceless stops.

• Students should concentrate on acoustic features including aspiration, VOT, and the distinction between voiced/unvoiced stops.

• Upcoming Laboratory Work

• Lab session will include creating spectrograms and identifying bursts, aspiration, formants, and potential voice bars in sounds.

• Screenshot submission required after labeling tasks.

• Next Steps in Learning

• Future sessions will cover fricatives, nasals, and approximants, building upon today’s knowledge of stops.

• Class Organization

• Reminder of Zoom logoff timing and organization for groups presenting their research headlines and final project discussions.