Reduction In Continuous Speech

The study of phonetic variation is the main part of studies on language change.Different phonological environments have different impact on phonetic variation. Theresults of studies on phonetic variation will deepen understanding of speech.Reduction widely exists in communicative speech, but it lacks systematic researches.This paper uses the acoustic phonetic analysis to study different acousticinformations on aspects of duration and intensity and formants of intervocalic stops inunstressed syllables of male announcers in VOA News in causal speech in the periodfrom2011to2013. To obtain acoustic informations about consonant realizations,PRAAT is used to analyze several aspects of duration, intensity and formant structureof/p/,/b/,/t/,/d/,/k/,/ɡ/in different styles (citation-form words and subcontinuousspeech) and in different phonological environments. Then this paper shows therelationship between the duration of stop and the distance between preceding voweland following vowel and between the intensity of stop and the intensity of precedingand following vowel. Then, the comparisons are conducted both between voiced stopsand voiceless stops and in different places of articulation in these vowelenvironments.The results of the study are represented: on the whole,/p/,/b/,/t/,/d/,/k/,/ɡ/aremore reduced in continuous speech than them in citation-form words, and the durationand the intensity and the proportion of formant of/p/,/b/,/t/,/d/,/k/,/ɡ/are differentin different vowel environments. Specific performances:1./p/has the most reductionin F-F./b/in F-B has the least reduction./t/in L-L has the least reduction, and in F-Bhas the most reduction./d/in H-H has the least reduction./k/in L-L has the leastreduction./ɡ/in L-H and B-F has the most reduction, and in F-F has the leastreduction.2. As for the relationship between the durations of stops and the distancesbetween preceding and following vowels, dental stops and most/p, b/have theshortest durations between different corner vowels and they have the longestdurations between the same vowel and the distance is not relevant to the durations of velar stops/k, ɡ/. As for the relationship between the intensities of stops and theintensities of both preceding and following vowels, the intensity of most/p/,/b/,/t/,/d/, k/,/ɡ/is directly proportional to the intensities of both preceding vowel andfollowing vowel.3. The duration of a voiceless stop (/b/or/ɡ/) is shorter and theintensity is larger than those of a voiced stop (/p/or/k/) when the voiceless stop andthe voiced stop belong to the same kind of stops in different vowel environments.Dental stops/t, d/have shorter durations and larger intensities and bigger proportionsof ‘strong formant’than those of bilabial stops/p, b/or velar stops/k, ɡ/.This paper studies acoustic features of stops in General American in causalspeech and the result provides new speech reduction data for English teachers toconduct more effective English phonetic teaching and for the persons who designmachines of phonetic recognition to make more accurate tools of phoneticrecognition.