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During modal voicing, the vocal fold vibration creates a regular buzz that by itself sounds quite far removed from natural speech. In fact, it resembles the squawking of a party noisemaker. Likewise, the basic sound of whisper is just undifferentiated noise and is not at all speech‐like. You don't actually hear these or other phonation types in their raw form, however, because of the way in which the SUPRALARYNGEAL VOCAL TRACT (SLVT) modifies the airstream on the way out. The SLVT is the long tube‐like chamber extending from the larynx upward, with a right‐angle turn into the oral cavity and another turn into the nasal cavity. Because of its RESONANT properties, the actions of the SLVT alter the buzz generated by the vocal folds, giving it the characteristics of intelligible speech. When the speaker configures the structures within the SLVT to modify the airstream, consonants and vowels are created. This process, known as ARTICULATION, shapes human vocalizations into meaningful utterances.

To illustrate articulation, let's consider the word tea, consisting of two sounds: the consonant /t/ and the vowel /i/. If you prepare to say the consonant and take note of what happens before you actually produce it, you'll feel the apex (tip) of your tongue make contact with the top of your mouth just behind your teeth at a bumpy region called the alveolar ridge. This gesture blocks the outward airflow altogether. When you release the obstruction, you create an explosive pop followed by a short puff of air. You have just articulated an apico‐alveolar plosive consonant. Notice also that as you release the /t/, your tongue is in position for articulation of the vowel /i/ that follows it. A short time after the /t/ release, your vocal folds will begin to vibrate to produce the voicing needed for the vowel.

Figure 2.7 shows a number of other parts of the vocal anatomy that are used for articulation. Moving from the upper teeth inward, the top of the oral cavity is the location of the alveolar ridge, the HARD PALATE, and then the soft palate or VELUM. The velum terminates at the UVULA, the small piece of tissue hanging in the back of the mouth.

Going back still farther, we arrive at the pharynx. You can see the pharyngeal wall when you look as far back as possible into your throat with a mirror. What you see is a region of the SLVT called the oropharynx. Lower down is the laryngopharynx, which is just below the EPIGLOTTIS, the flap‐like structure that assists with swallowing. At the top and behind the nasal cavity is the nasopharynx. The region between the nasopharynx and oropharynx, called the VELOPHARYNGEAL PORT, plays an especially important role in speech. Most often, during breathing, we keep this passage open by allowing the velum to remain down (as shown in Figure 2.7). In this configuration, air flows freely from the lungs through the nose. In speech, however, the velum is usually raised so that it makes contact with the pharyngeal wall and prevents nasal airflow. For most consonants and vowels of English, this closure is maintained. However, for nasal consonants, such as the /m/ in mouth and the /n/ in nose, the velum is kept down, giving these sounds their characteristic nasal quality.

The tongue is divided roughly into the regions shown in Figure 2.8: the apex (already mentioned), the lamina (or blade), the front, and the dorsum (back), as well as the radix (root), which is farthest back and is not generally visible in the mirror.

Figure 2.7 Detailed vocal anatomy

(Source: Adapted from https://commons.wikimedia.org/wiki/File:Blausen_0770_RespiratorySystem_02.png)

Figure 2.8 Parts of the tongue