Acoustics of Sonorant Consonants (and more)

1. Acoustics of Sonorant Consonants(and more)

2. NASALSAs a manner class, nasals are characterized by several properties of the nasal murmur: (1) a high-intensity low-frequency “nasal formant” in the vicinity of 250-300 Hz; (2) low-amplitude, wide bandwidth higher-frequency formants; (3) zeros or anti-formants whose frequencies vary with place;as well as nasalization into and out of the murmur. The characteristic low amplitude of nasal murmur is due to: Damping (nasal sounds have greater surface area, hence walls of vocal tract absorb more sound than for non-nasals) Zeros (absorb acoustic energy) Note: There is high interspeaker variability in nasal murmurs due to variation in the anatomical structure of the nasal cavities.

3. nose mouth pharynx ZerosNasals involve a side-branch resonator.Side-branch resonators introduce zeros (anti-resonances)due to impedance (opposition to sound transmission).That is, opposition to energy transmission (in this case, energyin the oral cavity) results in components in that frequency regionbeing trapped and not being radiated into the atmosphere ( = zero).The frequency of the trapped energy correspond to resonant frequencies of the oral cavity in a given configuration. Therefore (oversimplifying somewhat...), the longer the oral cavity (e.g., bilabials), the lower the frequency of the zeros.

4. Place of articulation in nasalsThe traditional view of nasals is that the murmur cues manner and formant transitions (into/out of the nasal) cue place. But the evidence now is that both murmur and transitions provide place information.Murmur: Zeros contributed by the mouth side-branch influence the spectra of nasals in place-specific ways.F2 transition: Although nasalization into/out of nasal consonants influences the spectrum, in general F2 transitions are similar to those of corresponding oral stops.For NV sequences, most research in the past 15 years has focused on the region of the release of the oral closure in nasals—i.e., the region of most rapid spectral change (e.g., last 2 pulses of murmur + first 2 pulses of the transition). Labials show rapid increase in energy in lower frequencies while alveolars show a rapid energy increase in higher frequencies.

5. More on place of articulation in nasalsAlthough the perceptual evidence is that listeners can use information from both the nasal murmur and transitionsin identifying nasal place, in general place is less accurately detected in nasals than in most other consonant types, especially when nasals are in coda position. Evidence of relatively poor place identification in nasals comes from experimental evidence (e.g., measures of perceptual confusion) as well as from linguistic patterns of allophonic or morphophonemic variation and sound change.For example, cross-language patterns of assimilation in N-C clusters show that it is nearly always the N, and almost never the C, that assimilates place (e.g., English impossible [mp], intolerant [nt], incoherent [Nk]).

6. VOWEL NASALIZATIONCoupling between the oral and nasal cavities during vowel production also adds pole-zero (formant—anti-formant) pairs to the spectrum, with the most prominent pair being in the low-frequency region.The result is that the F1 region of a nasal vowel is generally “flattened” (with a wide bandwidth and low amplitude) relative to that of the corresponding oral vowel. The frequency of the nasal formant in the F1 region tends to fall above F1 for high vowels and below F1 for low vowels.

7. Perceived height of nasal vowelsBecause vowel nasalization can heavily influence the F1 region of the vowel spectrum (which primarily correlates with vowel height), it is not surprising that the perceived height of corresponding nasal and oral vowels often differs. To think about:Relative to their oral counterparts, nasalization tends to lower the perceived height of high vowels and raise the perceived height of low vowels. WHY? HINT: Think about the location of the nasal formant relative to F1.

8. mouth pharynx [ala] zero LATERALSLaterals also involve a side-branch resonator formed by thetongue blade which adds a zero to the lateral spectrum at theresonant frequency of this short side branch. Laterals havehigher-amplitude acoustic energy in the lower-frequencies thanin the higher frequencies.

9. English /®/English /®/ has constrictions in the pharynx, in the alveolar-palatal region, and at the lips. Modeling its acoustic properties has been challenging, particularly in terms of predicting the low-frequency F3 characteristic of /®/.Recent models suggest that /®/ involves a sublingual sidebranch from the front cavity, with F3 as a resonance of the large-volume front cavity that includes the front cavity proper plus the volume of the sublingual cavity. (The sidebranch also contributes a zero whose frequency is determined by the length of the sublingual cavity.)

10. Vowel-like Sonorant Consonants Articulatorily, [j] is the approximant counterpart to [i]. [w] is the approximant counterpart to [u]. [Á] is the approximant counterpart to [y].On this basis, you should be able to predict their relative F2 frequencies...

11. F2 frequency High Mid Low High Low l F3 frequency j w ® English Approximants

12. BREATHY, CREAKY, and MODAL VOICEStops, some approximants, and vowels in the world’s languages differ in the state of the glottis during voicing. During a glottal cycle, the glottis is open longest in breathy voice, less in modal voice, and shortest in creaky voice. The resulting differences in the glottal waveforms for these phonation types influence the overall output spectrum. In general, in creaky voice, there is more energy in the F1-F2 region than in modal voice. In breathy voicing the first harmonic (F0) dominates the spectrum. Also, creaky voicing tends to be more irregular (more jitter) while breathy voicing may have noise in the higher frequencies.

13. lax [tal] ‘moon’ tense [t*al] ‘daughter’ Korean stopsKorean distinguishes 3 types of stops that differ in laryngeal activity and in the timing that that activity relative to supralaryngeal articulation: tense, lax and aspirated stops. Aspirated stops have longer VOT than lax or tense. Lax and tense differ from each other in H1-H2 (i.e., prominence of H1 relative to H2).