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articulation can be divided into the locations indicated in Figure 4. It is possible to have 17 places of articulation for consonants (Ladefoged and Maddieson, 1996). Con- sonants are also distinguished by the manner in which they are produced. For example, plosives are created by stopping the airflow in the oral tract and quickly releasing it as in the sound [p] in English. Fricatives are produced by making a tight constriction in the oral tract and creat- ing turbulent airflow through the constriction, as in [s] in English. Laryngeal contrasts, as we have already seen, include voicing and voice quality and aspiration (a period of voicelessness following a plosive release). The airstream mechanism (how we control the flow of air in speech) is what a speaker manipulates to power speech and can be realized as pulmonic egressive, glottalic egressive/ejective, glottalic ingressive/implosive, or velaric ingressive/click. Egressive sounds are created by outward airflow; ingressive sounds are created using inward airflow.
In addition to the segmental speech sounds, there are suprasegmental aspects of speech. A language’s supra- segmental acoustic features include whether it is a tone language (e.g., Mandarin and Vietnamese, as seen in the Mandarin example), a stress language (e.g., English and Hawai’ian), or a pitch accent language (e.g., Japanese and Western Basque). The acoustic features of suprasegmen- tal aspects of speech prominently include fundamental frequency as well as duration and intensity.
Phonotactics and Complex Combinations
A distinguishing characteristic of many languages is how they combine sounds, also called phonotactics. Although most languages have fairly simple phonotactics, some, like English, have much more complex combinations of segments as syllables as in the word sports, with a fricative ([s] in this case and plosive ([p] and [t]) combinations. A handful of known languages have very complex phono- tactics. One example is Tsou, an Austronesian language spoken in Taiwan by about 4,000 speakers (Eberhard et al., 2019). Most of its consonants and vowels are com- monly found in other languages. Unlike most languages, however, almost all of the two-way combinatorial pos- sibilities of consonants are attested to in clusters at the beginning of words, resulting in many very rare com- binations (Wright and Ladefoged, 1997). The examples (from recordings in Wright, 1996) in Figure 6 illustrate combinations of [fk], [kʃ], [tm], and [pŋ] at the beginning of words. One of the interesting features in Figure 6A (see
Multimedia5 at acousticstoday.org/tuckermedia) with the fricative-stop cluster is the amplitude of the labiodental fricative. It has a much higher intensity, and it is longer than when it occurs in languages that only permit it to occur preceding a vowel. Figure 6B is interesting because of the extremely short vowels in comparison to the frica- tives (see Multimedia6 at acousticstoday.org/tuckermedia). Figure 6, C and D, is interesting in part because they have often been misperceived in impressionistic transcriptions as having an extra syllable (see Multimedia7 and 8, respec- tively, at acousticstoday.org/tuckermedia).
Nonpulmonic Airstream Mechanisms
Languages differ not only in how they use sounds but also in what sounds they have, how those sounds are made, and how they combine the sounds. For example, although all languages excite the vocal tract with pulmonic-egressive powered sources (at the larynx for vowels and at various points along the vocal tract for sounds with aperiodic
    Figure 7. A: midsagittal view of the speech articulators illustrating an alveolar ejective. Arrow, direction of laryngeal movement. B: waveform (top) and spectrogram (bottom) of [tɬ’i:ze], “a horse fly” in Dene Sųłiné.
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