Introduction to Phonetics Ch. 3 (Ogden): Representing the sounds of speech Reading Notes PDF

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Introduction to Phonetics: Chapter 3 – Representing the sounds of speech Week 20 LING223 Phonetics Reading Notes  Phonetic transcriptions built on the apparently simple alphabetic principle of 1 symbol for each sound  There are representations based on acoustic analysis (waveforms & spectrograms). o Help us see that despite our impressions, reinforced by an alphabetic writing system, sounds of speech are constantly changing o More commonly used in phonetics, make it possible to see individual aspects of sounds separately  Phonetic Transcription o Represent an analysis of the sounds we can hear (using written letters) o Transcriptions often have a linguistic status  Some transcriptions are more impressionistic, try capture what we hear rather than make claims about the significance of what we hear for making meaning o Phonetic values of letters are variable across languages  IPA o Most common tool for phonetic transcription is the alphabet of the International Phonetic Association  Both the Association and Alphabet commonly known as ‘the IPA’ o IPA is a set of tables containing symbols organised into rows and columns labelled with terms that have agreed meanings  Unlike the random order of the Alphabet o Rows of the Consonant chart groups sounds according to manner  1st row – Plosives [p b t d ʈ ɖ c ɟ k g q ɢ ʔ]  Rows below have sounds with progressively more open stricture o Columns organise symbols by place of articulation  Leftmost column – Bilabial  Following columns contain symbols for sounds made progressively further down the vocal tract  Rightmost column – Glottal o Symbols of the IPA presented in a number of tables  Main = Pulmonic egressive consonants and vowels  Other tables have non-pulmonic consonants, diacritics and suprasegmentals (aspects of sound which relate to things like length, phrasing, intonation, etc)

 Principles of IPA o Makes some assumptions about the nature of speech o According to IPA, ‘Some aspects of speech are linguistically relevant whilst others… are not’. Phonetic transcriptions should only have info that is linguistically meaningful o Physical differences, caused by things e.g. gender, age, physical state (out of breath) mean people sound different But these are physical not linguistic differences, phonetic transcription doesn’t capture them o ‘Speech can be represented partly as a sequence of discrete sounds or segments’  Segment  A piece of something that has been chopped o IPA claims that speech isn’t made of segments but that we can represent it as segments o IPA establishes 2 major types of segment = Consonant & Vowel  Consonant: Sounds produced with some kind of constriction in the vocal tract. Can feel, see and hear where the constrictions are made and what kind of constriction they are  Vowel: Produced without a constriction in the vocal tract, harder to sense how they’re articulated. o Suprasegmentals  Aspects of speech which persist over several segments  E.g. duration, loudness, tempo (speed), pitch characteristics and voice quality. May include lip rounding  Often thought as the ‘musical’ aspects of speech  Important for marking all kinds of meanings, in particular speakers’ attitudes/stances to what they’re saying (or the person they’re saying it to)  Marks how 1 utterance relates to another (e.g. continuation or disjunction)  Different situations make different demands of a transcription  One important point is the amount of detail that a transcription has o Transcriptions can have as many details we can observe = Narrow o Transcriptions can use a restricted set of symbols, therefore glossing over many phonetic details, as they’re predictable from the context, not important in distinguishing word meanings = Broad  Typical in dictionaries

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o Using familiar Roman letter shapes = Simple Transcriptions sometimes used to compare sounds Transcribing different varieties of a single sound when we hear them produces a comparative (narrower) transcription Systematic transcriptions limit the number of symbols used to a given set o In some circumstances, there are choices about how to represent sounds o Phonemic transcriptions are by definition, systematic o In a systematic transcription, set of available symbols is restricted Phonemic transcriptions embrace the concept that 1 linguistically meaningful sound should map on to 1 symbol, necessarily broad Allophonic transcriptions capture such details, predictable Narrower than phonemic transcriptions Impressionistic transcriptions use the full potential of the IPA, necessarily narrow For vowels its more difficult to provide a systematic transcription system o As vowels are extremely variable across varieties of English Citation form = Word spoken slowly in isolation, found in dictionaries o Concatenates the citation forms for each word in the sentences Broad transcription – All the symbols used represent sounds use to distinguish word meanings o Uses a small, limited set of transcription o Can add allophonic details making it ‘narrower’

 Vowels before nasals in the same syllable – e.g. ‘think’ are often nasalised o Velum is lowered at the same time as a vowel is produced, allowing air to escape through both the nose and mouth o Marked by diacritic over the relevant symbol  Voiced final plosives and fricatives (e.g. ‘need’, ‘shoes’) often produced without vocal fold vibration all through the consonant articulation when they occur finally and before voiceless consonants  Phonetic details are sometimes predictable in English  Since labiodental articulations don’t involve the same articulators as alveolar ones, 2 articulations can overlap o Represent this with diacritic [  ] meaning 2 articulations occur simultaneously

 Sounds of speech made by changes in air pressure caused by airflow through the vocal tract o As air moves it causes perturbations which the ear picks up o Ear converts physical movements in the air into electrical signals sent to the brain, where processing of other kinds occurs  Technology makes it possible to convert these changes of air pressure into pictures, static and unchanging, these pictures allow us to examine more detail of talk as it happened  2 main kinds of acoustic representations: o Waveforms o Spectrograms  Wave forms = Graph o X-axis = Time, usually scaled in seconds or milli-seconds o Y-axis = Amplitude, representation of loudness  The bigger the displacement from the baseline, the louder the sound is  Spectrograms = Pictures of speech o Provide more complex information than waveforms o Times, as in waveforms marked on the x-axis o Frequency on the y-axis o Amplitude reflected in darkness  Louder a given component in the speech signal is, the dark is appears  3 main kinds of sound easily distinguishable on a spectrogram o Periodic = Regularly repeating  In speech, periodicity associated with vocal fold vibration, so periodic waveforms are associated with voicing  Each major peak in a periodic waveform corresponds to 1 opening of the vocal folds  One complete repetition called a cycle or period o Aperiodic = Random  Continuous = like fricatives ([s f])  Transient = (short and momentary) like [p t k]  The number of complete cycles the vocal folds make in 1 second = Fundamental frequency (f0) o Measured in Hertz (Hz)

 In spectrograms, periodic signals have 2 important visual properties o Vertical striations Correspond to the opening of the vocal folds; each time the vocal folds open and air escapes, there is a sudden increase in amplitude Shows in the striations in the spectrogram which line with the peaks in the waveform Voicing regularly spikes in a waveform, corresponding regular striations in a spectrogram o Formants Darker horizontal bands running across the spectrogram Named counting upwards 1st = F1 2nd = F2 etc They’re natural resonances  Each configuration of the vocal tract has its own natural resonance  Aperiodic sounds have no repetition, random noise o Friction noise generated when the airflow between 2 articulators is turbulent o Correlate of this in a waveform is more irregular/random pattern than periodic  Lacks the regular ups and downs of a periodic waveform  Transient Sounds are aperiodic sounds which come and go quickly o E.g. knock on a door, cutlery rattling against eachother, firework exploding o Main source is the explosive release of a closure, e.g. releasing a closure for [p] or [k] o Others are the tongue/lips coming apart as someone starts to speak, bubbles of saliva bursting in the mouth, the velum being raised, sides of the tongue making contact with the teeth or cheeks o Show as spikes in a waveform Appear as dark vertical lines in spectrograms which only last a short time  Acoustic representations are rarely static like transcriptions  Transcriptions and acoustic representations capture different kinds of truth about speech o Transcriptions – Distinct sounds

 More general o Acoustic = In speaking, articulators are rarely static  Capture details and facts about 1 utterance on 1 occasion by 1 speaker  Less useful in representing facts about language, easily subject to change  When articulators move, these movements have acoustic consequences, this fluidity helps make everyday speech easier to perceive o Both are subjective Approximants  Most profound class of consonants. Share many characteristics of vowels including characteristic formant patterns  Palatal Approximant o [j] – Low F1 due to tongue body being close (raised) High F2 due to tongue body being fronted o No real clear beginning or end  Labiovelar Approximants o Lips are rounded and tongue back is raised towards the velum o First formant moves downwards, while F2 gets much lower due to both tongue backing and lip-rounding o As approximations are made, vocal tract narrows, amplitude diminishes o [w] = Double Articulation  Open approximation at the lips  Lips are closely rounded, not close enough to produce friction noise  Tongue back at the velum  Tongue back raised up to the soft palate  Velum is raised, air can’t escape through the nose  Vocal folds vibrate, so there is voicing o No real clear beginning or end  Lateral Approximants o Syllable-initial vs Syllable-final lateral  Syllable-initial is clearer  Has a higher F2 than syllable-final lateral  Has a more abrupt ending than the beginning of the syllable-final

 Transition out of the lateral portion is rapid, unlike syllable-final which has a slow transition  Rhotic Approximants o Common property of having a low F3 (around 1800 Hz) o As most rhotic versions involve tongue body movement, which is relatively massive and slow to move, their acoustic properties tend to be extensive in the time domain o Plosives  3 phases of a typical plosive can be seen in a waveform and spectrogram  Closing Phase o Formants move slights – Movements called ‘transitions’ o Transitions correspond to movements of the articulators into the closure o Although there’s some voicing during closure, its quiet and its amplitude diminishes until it eventually stops  Hold Phase o Amplitude drops significantly as there is no airflow in the vocal tract o On release there’s a transient burst, seen as a sudden increase in energy, in the waveform and spectrogram  Release o Voicing starts again very soon after the release of the closure Fricatives  Voiced o Voicing and friction don’t overlap o Friction is loud and turbulent compared to voiceless fricatives o Friction is long in duration compared to voiceless fricatives  Voiceless o Voicing and friction may (but do not necessarily) overlap o Friction is quiet (low amplitude) compared to voiced fricatives o Friction is short in duration compared to voiced fricatives Nasals  Coming out of a nasal to a vowel, oral closure must be released, velum must be raised to block airflow through the nasal cavity

 2 articulations are generally simultaneous, when the oral closure is released, airflow becomes oral o Producing a discontinuity in volume, can be seen in waveforms and spectrograms as a rapid change in amplitude  Sometimes movements of the velum can be seen in a spectrogram  Abrupt change in amplitude as nasality ends  Some areas of low amplitude, such as around 1600Hz o Due to the nasal cavity absorbing some of the acoustic energy, gaps (called zeroes) often evident on spectrograms  Although formants are visible during the nasal portion, they’re less distinct than in the vocalic portion o Because the formant peaks are wider, making them quieter and less visually prominent o Particularly noticeable in F1...