How is articulation organized? Speech Science IX How is articulation organized?

Articulatory states vs. articulatory gestures Speech sound description is based on the positions or states of the articulators not on their movements The movements from one position to another are not part of the definition of the sound structure of a language. The symbolic representation (phonetic transcription) of an utterance also suggests that the position or state of the articulators (the configuration) is the most important aspect of the sound structure. A film of speech being articulated shows that some part of the articulatory system is almost always in motion. To explain how speech works, we need a model of how the movements are controlled, a model of gesture organization. In the tradition of phonetic description, we rely a great deal on auditory and visual observation, particularly on self-observation (we hear an utterance – often a word or syllable – imitate it, and when we are satisfied that we have produced the same-sounding utterance, we try to work out what we have done articulatorily to produce it). This necessarily meant that we capture the part of the sound production which, in our view, defines the essence of that sound, i.e., mostly the position that has to be reached to make the sound possible: the position of jaw, tongue and lips for a vowel (with accompanying voicing) the place of constriction for the fricative (with or without accompanying voicing) the place of closure for the stop (with or without accompanying voicing) Only in the case of a diphthong, an affricate or an aspirated (vs. unaspirated) plosive, is anything said about temporal characteristics, about a change of state. --------------- Of course phoneticians must have always been aware of the articulatory movements, but even when they began to be captured in instrumental investigations (they were first described in terms of “Anglitt” and “Abglitt” by Menzerath and De Lacerda just before the 1939-45 war) they were seen merely as the consequence of having to move from one state to another. The complications that come from considering the control of muscles were not yet on the horizon.

Topics Sound categories and articulatory variability. How do we control our articulation? At what level do we control our articulation? - individual muscles? - gestures for individual sounds? - sequences of gestures for syllables? - …. for words? Reading: BHR, Chap. 5, pp. 134-173 ff. (Variation, Feedback, Prod.-Models) P.-M. 1.4,8. pp. 64-78 (Steuerung) If we want to consider how articulation is organized rather than just categorizing sounds and describing which sounds are produced in an utterance, we need to consider the issues listed above. Behind these points there are a host of other questions.

Sound Variants A problem with definition by articulatory state is the potential “many-to-one” relationship between speech events and their causes. a) One acoustic event (speech sound) can result from different articulatory configurations (= “articulatory compensation”) b) One articulatory configuration can result from different patterns of muscular activity (= “neuromuscular compensation”) The first thing that stands in the way of assuming a simple catalogue of neural commands controlling each sound is the fact that there appears to be both “articulatory compensation” and “neuro-muscular compensation”. This is the term that is used to cover the fact that not everybody does the same thing to produce the same sound. The many-to-one relationship only operates in one direction. Acoustic theory can predict what the signal should be if the articulatory configuration is known, but not vice versa. I.e., if we observe a particular signal, we cannot be certain how it was produced (despite the fact that traditional “articulatory and auditory phonetics” is based on learning particular articulatory patterns for particular sounds!) The compensation can operate at two levels, the macro-level of the articulatory positions, and at the micro-level of the patterns of neural commands.

Sound Variants (example) articulatory compensation “Standard” vs. Saarland < ich > Articulatory alternatives have been observed (x-ray data) for the postalveolar fricative /S/ (and its voiced counterpart). With no auditorily distinct change of quality, the fricative can be produced with or without slight retroflexion of the tongue-tip. It is important to realise that we are talking of auditorily equivalent and functionally equal sounds (hence the same transcription symbol). The functionally equal but auditorily distinguishable variants of the German /C/ phoneme are (of course) produced with different articulations.

Sound Variants (other examples) • Another well-known example of articulatory compensation is the „American /r/“ ([]) The tongue may be a) turned back (retroflex) b) bunched • Lip-rounded vowels (like [y]) can be produced with strongly rounded, protruded lips, or with retracted tongue and neutral (or even spread) lips (with or without a lowered larynx). The American “R” sound also has a retroflex and a non-retroflex variant. In vowel production, where overall cavity length and the relations between cavities ant the front and the back of the mouth determine the resonance properties, adjustments of lip-protrusion (greater or lesser overall cavity length) and the raising or lowering of the larynx (also greater or lesser overall cavity length) together with adjustments to the place of tongue-palate constriction offer many compensatory articulatory settings.

Free variation vs conditioned variants • Articulatory differences (requiring different commands to muscles) are not only the result of having acquired a particular variant. • Sounds occur in context, and the gestures are different with every different preceding sound! • This makes the relationship between one speech sound (in linguistic terms “a phoneme”) and the commands to produce it complicated. So far, we have considered the production of sounds which are auditorily equivalent. It has long been recognized that in different contexts, functionally equivalent sounds (i.e. phonemes) can be different (for which the term “allophone” was coined). This fact is, however, only considered important (in phonology) if the result is a change of features (e.g., normally aspirated voiceless plosives are not aspirated after a syllable-initial fricative: Tal – Stahl); or (in speech technology) if the acoustic difference is such that it requires the training of different models (e.g. clear and dark /l/). But from the point of view of motor-control, any sound has as many variants as it has contexts. The muscle commands required to move the tongue-tip and blade to the same coronal occlusion behind the teeth will be different for each of the sounds it can occur after (and in German /t/ can occur after any vowel, any consonantal sonorant except /j/ and any voiceless obstruent). There seems therefore to be little relationship between the neural control of articulation and the level of phonological description!

Different movements in context Contextual differences in gestures affect every part of the articulatory patterns. Here, chin and tongue-tip interaction. Zungen-spitze Kiefer-öffnung i t e a Here we see a simple example of the consequences for tongue and jaw control of producing /t/ in an /i __ / vs. an /a__/ context. In the one case the tongue tip has to be raised less and lowered more because of the opening jaw (from /i/ to /e/) and in the other case it is raised more and lowered less because of the closing jaw (from /a/ to /e/).

Context variation: Coarticulation Example: Tüte Tongue tip Lip- rounding The effects of neighbouring sounds on one another is given the name “coarticulation”. However, the subtle and not easily observable coarticulation shown in the preceding slide is often overlooked. The more obvious coarticulation, and the kind referred to in phonological discussions, is when a phonological feature changes because of the influence of one sound on the preceding or following sound. The word “Tüte” must be produced with lip-rounding present during the articulation of the first /t/ (otherwise the word would sound like [tjyt]) and the rounding must stop during the closure of the second /t/ (otherwise the word would sound like [tytw]). So it is clear, that the motor control for sounds varies not only for each sound that precedes a particular sound, but also as a function of many of the sounds that follow it. [ t u t  ] When a property of one sound affects the way in which a neighbouring sound is produced, we call the effect “coarticulation”. Here lip-rounding in the initial /t/ of „Tooter“.

What does this say about speech production? • The motor activity involved in producing speech sounds is much more complex than the (relatively simple) phonetic- phonological categorisation of speech sounds • We have to decide whether there is (or can be) any link between linguistic description and production models The recognition of the complexity behind the production of speech sounds in sequences within syllables and words may be something which makes us feel some degree of wonder at our abilty to articulate so effortlessly (and our ability to learn it at such an early age). It may also make us appreciate that things may easily go wrong with the process, so that speech disturbances such as stuttering and lisping can result. But it also raises the question of the relationship between phonological theory and motor control. It would clearly be very damning for the relevance of phonology if wecould find no link at all between the way speech production is organized and way speech structure is represented linguistically. …. It would be unfortunate if we had to say that the two had nothing to do with each other!

But the observations also tell us …. • The acoustic ( perceptual) identity of sounds seems more important than the motor equivalence • When we learn to articulate, we match our own production to what we hear. The acoustic patterns from other speakers are our only models … In terms of articulatory differences between individual speakers, we need not be too worried. The model of articulatory learning (speech-sound acquisition) that is most widely accepted at present is one based on the acoustic similarity, and the perceptual equivalence of the sounds that different people produce. (Perkell, J.S. et al. 2000, Journal of Phonetics 28, 233-272) It is assumed that from the babbling phase onwards, we match the feeling we get while moving our articulators with the sounds that we produce. In the babbling phase we listen to ourselves, and are learning what the acoustic consequences of the different movements are. In the language-learning phase, we are listening to the people around us as well, so we inevitably match our own production to the ambient sounds and learn the local dialect. …… nobody shows us how to move our lips, tongue, velum or larynx …….

… although … • There seems to be an innate ability to imitate peoples‘ facial expressions This has been systematically observed in very young babies, who mimic their mother‘s expressions. • So there may be some visual input as well as the predominant acoustic input to the speech learning process. How much the visual mimicry ability that babies exhibit almost from birth helps in the acquisition of articulatory patterns is an open question. But only a small fraction of the articulatory activity is visible/observable.

Must our normal production processes be related to processes used in learning? • Theories of speech production do not always model articulation from a perceptual standpoint. • Linguistic (phonological) models of sound systems are concerned with the patterns of sound produced, not with the processes that are required to produce them (BHR p. 152 f.) Not all frameworks modelling spoken language take the perceptual target as their point of orientation. The traditional descriptive “models” are concerned with the structures and patterns, and they were arrived at before the existence of modern instrumental methods made it easy to capture the processes that unroll during the production of speech. None of them were concerned with the question of how the processes were controlled. The IPA system is articulatorily orientated. Distinctive Feature theory (more abstract) can be articulatory or acoustic.