1. Airflow from the lungs:
- Air is expelled from the lungs through the trachea (windpipe).
2. The vocal folds:
- Two folds of tissue called vocal folds (or vocal cords) are located inside the larynx.
- These folds are normally open, allowing air to pass through freely.
3. Phonation:
- To produce sound (phonation), the vocal folds close together.
- As air from the lungs rushes through the narrow space between the vocal folds, it causes them to vibrate rapidly.
- This vibration creates sound waves that we perceive as our voice.
4. Pitch control:
- The pitch of the voice is determined by the tension of the vocal folds.
- Tighter vocal folds vibrate faster, producing a higher pitch.
- Looser vocal folds vibrate slower, producing a lower pitch.
5. Loudness control:
- The loudness of the voice is determined by the amount of air pressure from the lungs.
- More air pressure results in louder sounds.
6. Resonance:
- The sound produced by the vocal folds is further shaped and amplified by the resonators: the pharynx (throat), the oral cavity (mouth), and the nasal cavity (nose).
- These cavities act as filters, modifying the sound to create different vowel and consonant sounds.
Types of speech sounds:
- Voiced sounds: Sounds produced with vocal fold vibration (e.g., "m", "v", "a").
- Unvoiced sounds: Sounds produced without vocal fold vibration (e.g., "f", "s", "th").
Important points:
- The larynx is not only involved in speech production but also plays a crucial role in breathing and protecting the airway from foreign objects.
- The complex interaction of airflow, vocal fold vibration, and resonance allows for a wide range of speech sounds.
- Understanding how the larynx works provides insights into the nature of human voice and the mechanisms of speech production.