Acoustic & Auditory Phonetics is by Keith Johnson - Book Report/Review Example

Book Report The book Acoustic & Auditory Phonetics is by Keith Johnson with the third edition coming out in 2011. The edition is wholly extensive and revised to provide students with an extensive preamble to the physics of speech while at the same time maintaining a balance of scholarly severity and accessibility for the readers. The updates in the book offer and reflect new and current progresses in the field under study. Some of the key features in the book are; student friendly approach to speech with a big engagement on side-bars regarding related topics, which the students face in the field of physics of speech. The author has also put across suggested areas for further readings, and exercises which are in a bearing to appraise and develop upon the material in each chapter while also providing answers to selected questions. A major inclusion in the book is a chapter in speech perception and extra segments on digital filtering and cross-linguistic vowel and consonant perception. The discussion in this paper will draw its basis on chapter five of the book, providing a summary and insight into what the author has written. Speech perception Chapter five of the book Acoustic & Auditory Phonetics deals with speech perception, the title under which, the chapter appears. The emphasis comes from the saying “we speak in order to be heard, in order to be understood” the author insists that when one is listening to another, they are likely to focus on the words the speaker is saying, rather than the pronunciation of each word. However, in some cases a word pronounced differently from the way a listener understands it may jump out and catch the attention of the listener. The author of the book, therefore, submits that such a situation, which is listening to the sound of words and not just their meaning, the listener gets engaged in what scientists call speech perception. Speech perception involves listeners listening and detecting mistakes in the pronunciation of words, instead of meaning to these words, something that may be missed in a normal conversation. The focus of this chapter, chapter five; speech perception, is on the sounds of speech rather than the words involved in a conversation. Auditory Ability Shapes Speech Perception The shaping of speech perception is through the general properties of the human auditory system that establish what can and cannot be heard, how sounds close together can be associated with each other, and what signals can be recovered in any related fragments. One of the two examples of, how the auditory system limits speech perception is drawn from the differences between aspirated stops and stops which are not aspirated, shown by the VOT. The VOT measures the delay in voicing onset after a stop release burst. In aspirated stops, the vocal folds remain open for a short time after the release of the oral closure of the stop. This explains why there is a short puff of air produced in voiceless aspirated stops. Some languages may have a 30ms VOT delay between stops, which are aspirated, and those which are not, which affects one’s auditory system. The importance of this is 30ms VOT is that listeners do not notice an onset asynchrony until it has reached 30ms Phonetic Knowledge Shapes Speech Perception It is essential to note that all speech perception phenomena are not necessarily determined by the auditory abilities. There are two effects that emerge from one’s knowledge of phonetics. These are categorical perception, and phonetic coherence. Token Number F2 onset f3 onset Identified As 1 1480 2750 "da" 2 1522 2562 "da" 3 1565 2375 "da" 4 1607 2187 "ga" 5 1650 2000 "ga" Table 5.1: a continuum, of synthetic consonant-vowel ranging from “da” to “ga”, in five acoustic equal steps The above illustration shows a series of syllables that have gradually changed from a “da” sound to a sound that sounds like “ga”. This phenomenon is referred to as a stimulus continuum. According to Bregman, auditory sensory experience forms a coherent picture of gestalt organizing principles that can be referred to as auditory sense analysis. When one is perceiving speech, it is possible to experience phonetic coherence with acoustic entities that ought to be incoherent in accordance with scene analysis principles. An illustration of coherent perception occurs when individual dubs audio “da” onto video “ba”, observers are likely to report audio “ba”, which is as a result of the closure of the lips. However, upon dubbing audio “ba” onto video “ga”, the result will not sound as either, but instead; it will be a “da”. This result in the creation of an illusion called McGurk effect, which goes to show that listeners combine the information from their ears to what they observe with their eyes so that they can come to a phonetic judgment about what is being said. Linguistic Knowledge Shapes Speech Perception The focus on linguistic knowledge is not just on phonological knowledge, but also the lexical effects in speech perception, which is to imply that hearing words is different from hearing speech sounds. In this sub topic, the idea is that speech perception gets influenced from the lexical status of sound patterns one is exposed to, although this is a contentious issue among scholars of physics of speech. It is a common understanding that listeners apply their knowledge of words in speech perception. Even in the event that one mishears speech sound and thinks that the speaker has mispronounced the word, research shows that listeners tend to hear words even when there is a failure in communication. Perceptual Similarity This method involves introducing test syllables to test subjects and asking them to identify the sounds in the syllables. Noise may be introduced measured in a ratio to the peak intensity of the syllable in a confusion matrix. One can also refer to this as the signal to noise rational; (SNR) and its measurements are in decibels. The data below explains why most children say “Kief” instead of “Keith” as “θ” was called “f” 85 times out of 232.   "f" "v" "th" "dh" "s" "z" "d" Other Total [f] 199 0 46 1 4 0 0 14 264 [v] 3 177 1 29 0 4 0 22 236 [θ] 85 2 114 0 10 0 0 21 232 [ð] 0 64 0 105 0 18 0 17 204 [s] 5 0 38 0 170 0 0 15 228 [z] 0 4 0 22 0 132 17 49 224 [d] 0 0 0 4 0 8 189 59 260 Table 5.2: Fricative confusions Maps from distances To get a perceptual picture of what caused the confusion from the confusion matrix, a map can be used. In a method, which is an extension of triangulation, called multidimensional scaling (MDS), one can produce a perceptual map from a confusion matrix. The achievement of this is through the conversion of confusions into distances. Works Cited Johnson, Keith. Acoustic and auditory phonetics Cambridge, Mass.: Blackwell Publishers, 2011. Read More