An obstruent (/ˈɒbstruːənt/) is a speech sound such as [k], [d͡ʒ], or [f] that is formed by obstructing airflow. Obstruents contrast with sonorants, which have no such obstruction and so resonate. All obstruents are consonants, but sonorants include vowels as well as consonants.
When a vowel follows an obstruent, the fundamental frequency in the first few tens of milliseconds of the vowel is known to be influenced by the voicing characteristics of the consonant. This influence was re-examined in the study reported here. Stops, fricatives, and the nasal /m/ were paired with the vowels /i,a/ to form CVm syllables. Target syllables were embedded in carrier sentences, and intonation was varied to produce each syllable in either a high, low, or neutral pitch environment. In a high-pitch environment, F0 following voiceless obstruents is significantly increased relative to the baseline /m/, but following voiced obstruents it closely traces the baseline. In a low-pitch environment, F0 is very slightly increased following all obstruents, voiced and unvoiced. It is suggested that for certain pitch environments a conflict can occur between gestures corresponding to the segmental feature [stiff vocal folds] and intonational elements. The results are different acoustic manifestations of [stiff] in different pitch environments. The spreading of the vocal folds that occurs during unvoiced stops in certain contexts in English is an enhancing gesture, which aids the resolution of the gestural conflict by allowing the defining segmental gesture to be weakened without losing perceptual salience.
The Japanese language has single/geminate obstruents characterized by durational difference in closure/frication as part of the phonemic repertoire used to distinguish word meanings. We first evaluated infants' abilities to discriminate naturally uttered single/geminate obstruents (/pata/ and /patta/) using the visual habituation-dishabituation method. The results revealed that 9.5-month-old Japanese infants were able to make this discrimination, t(21) = 2.119, p = .046, paired t test, whereas 4-month-olds were not, t(25) = 0.395, p = .696, paired t test. To examine how acoustic correlates (covarying cues) are associated with the contrast discrimination, we tested Japanese infants at 9.5 and 11.5 months of age with 3 combinations of natural and manipulated stimuli. The 11.5-month-olds were able to discriminate the naturally uttered pair (/pata/ vs. /patta/), t(20) = 4.680, p < .000, paired t test. Neither group discriminated the natural /patta/ from the manipulated /pata/ created from natural /patta/ tokens: For 9.5-month-olds, t(23) = 0.754, p = .458; for 11.5-month-olds, t(27) = 0.789, p = .437, paired t tests. Only the 11.5-month-olds discriminated the natural /pata/ and the manipulated /patta/ created from /pata/ tokens: For 9.5-month-olds, t(24) = 0.114, p = .910; for 11.5-month-olds, t(23) = 2.244, p = .035, paired t tests. These results suggest that Japanese infants acquire a sensitivity to contrasts of single/geminate obstruents by 9.5 months of age and that certain cues that covary with closure length either facilitate or interfere with contrast discrimination under particular conditions.
This vibration is easy to maintain when the air is emerging relatively freely from the lungs. In obstruents this is not so. Plosives and affricates are different from fricatives in that theformer contain an occlusion, a phase during their articulation when the flow of air emerging from the lungs is totally blocked. In fricatives the air is continuously escaping because there is a narrow gap between the articulators. But even in fricatives the airflow is significantly slowed down because of the narrowness of the gap. Obstruents with an occlusion are called plosives, those without are fricatives.
word finallyWord final lenis obstruents lose much of their voicing. Word final fortis obstruents are not aspirated: if aspiration is the voicelessness of the following segment, a plosive not followed by anything can hardly be aspirated. What distinguishes a word-final fortis and lenis obstruent is the length of the preceding vowel. If we compare bad and bat, we see that the vowel of bad is significantly longer than that of bat. The same is true in the case of fricatives: the most prominent difference between phase fɛ́jz and face fɛ́js or the verb use jʉwz and the noun use jʉws is in the length of their vowels. This is also the case if a sonorant consonant precedes the obstruent: tend vs tent, tens vs tense, killed vs kilt, cold vs colt.
The following chart summarizes the obstruent allophones in English. Only the labial pairs are given for plosives (p b) and fricatives (f v), the other pairs behave in the same way. (V́ means a stressed vowel, V̊ means an unstressed vowel, sonorant consonants may occur between the vowel and the obstruent.) 59ce067264