From: LAURA SLOCUM The common theme in this week's readings [(Pater et. al, 2004; Stoel-Gammon (1998); Edwards (2000); Beckman & Edwards (2000)] is lexical learning and the relationship between phonological and lexical knowledge in child language acquisition. Regarding Prater et. al (2004): 1) I know that sucking and visual attention are measures commonly utilized in infant studies. How reliable are these techniques in infant habituation studies? 2) "When first learning a word, fourteen-month-olds treat words that differ in the place of articulation of initial consonants as identical, even though they are able to distinguish them in a perceptual task." (p. 388) This is giving the infant a lot of credit for realizing the difference in task type (phonological versus lexical). How do we know the child is responding to the picture as a "lexical task" and isn't just responding to picture (visual) characteristics? 3) I think the authors should consider how adults approach lexical learning tasks and memory systems (phonological, semantic, lexical) in order to inform infant learning. How do they compare/contrast? 4) How does this inform practice? From: Kathleen Currie Hall Notes on: Pater, Joe, Christine Stager, and Janet F. Werker. 2004. The perceptual acquisition of phonological contrasts. Language, 80(3): 384-402. Summary: In this article, the authors extend a series of perceptual experiments with 14-month-olds, testing the difference between perception of phonetic distinction vs. phonological contrast. They find that even though children can hear distinctions between minimally different words in terms of voicing and place, when these words are actually paired with objects and the child tries to attach meaning to them, the phonetic differences are not noticed. Details: 1. Two hypotheses about the acquisition of perception: (a) because children start out being able to discriminate all possible contrasts, they must have very detailed phonetic representations of the words they hear and store in their mental lexicon. (b) as with production, perception proceeds gradually, and some contrasts are easier to perceive than others; even older kids can't always perform well on minimal word decision tasks. 2. They use a new-ish technique, the SWITCH method, to test these hypotheses. In this technique, the child is presented with a picture of an object accompanied by a spoken word, and is allowed to habituate to the pairing. In the test trial, the child is presented with either the same pairing or a "switched" pairing (e.g., same picture, different word), and the duration of the child's interest is measured. It is assumed that if the child pays attention longer to the switched pairing, it is because the child noticed the difference and is interested in this new information. This technique can also be used with two object-word pairings, where the "switch" reverses the pairings (a more difficult task). 3. Exp. 1: Replicate earlier double-object switch experiment using [bIn] and [dIn] instead of [bI] and [dI] to make sure that the fact that infants didn't notice the switch wasn't just because the words weren't English. Replicated the earlier results: the children didn't notice the switch -- seem to perceive [bIn] and [dIn] as the same when learning them in a sound-object pairing. (Note that earlier experiments have shown that when just listening to the sounds, infants this age CAN discriminate these sounds -- it seems to be an effect of the sound-meaning pairing that impairs discrimination.) 4. Exp. 2: Single-object pairing, voice contrast instead of place contrast ([bIn] vs. [pIn]). Same results: infants don't notice the difference. 5. Exp. 3: Single-object pairing; both voice and place contrast ([dIn] vs. [pIn]). Again, infants don't notice the difference. 6. Two main possible interpretations: (a) children actually encode these words e.g. [bin] vs. [pin] as same in their mental lexicons. (b) children are too busy trying to pair the sound with the meaning to notice the distinction -- an effect of processing only. The experiments presented here did not differentiate between these two interpretations. Either way, somehow the phonetic differences are not fully utilized in the phonological system. 7. BUT -- other similar experiments with words that the child knows indicate that the child _can_ pay attention to the difference! So the differences are only _partially_ encoded. 8. The authors (who favour the "processing overload" interpretation) claim that the phonological grammar of the child can be modelled in OT by having markedness constraints outrank faithfulness constraints (faithful = faithful to phonetic input of signal) by default. At first, and whenever processing difficulty is high, this pattern reigns, and phonetic differences are neutralized in the phonological representations. But when processing is easier for whatever reason, then faithfulness can take over and the contrast can be maintained. Questions: 1. p. 390 (and others) -- what qualified as "exposure" to one of the test words? Surely it's impossible for the parents to recall everything said in the child's presence in 14 months . . . ! 2. Not sure I buy their OT analysis . . . I like the basic idea (modelling the actual behaviour of the child with your phonological theory, the fact that it gives you the gradual/partial integration, etc.). But it seems intuitively very wrong. I understand the basic principle of needing to have markedness over faithfulness in OT learning systems, but here it seems very strange when applied to the phonetic input to the child. Essentially, isn't the baby saying (not consciously of course!) "Oops, every time I'm under a lot of stress, I keep forgetting that I should be maintaining whatever sounds I hear!" Why should the child posit anything other than the surface form that they hear? (Seems strange that the default is to in many ways be _more_ abstract . . . .) From: ASIMINA SYRIKA -p.386 'This set of results appears to indicate that when phonological representations are first acquired receptively they are indeed reduced in complexity relative to the adult form, encoding neither place nor voicing contrasts.' How can you tell that/when a phonological representation is acquired receptively? Why is it necessarily reduced in complexity? -I think I would like more information from the article on the familiarization technique used in infant speech perception experiments. On what grounds are the words chosen? Are children habituated to words that are unfamiliar to them or easy to produce? -I was just wondering whether infants with 'their exquisite perceptual abilities' (p.385) are also able to distinguish foreign accents. Is there any research of the kind? -p.399 'However, we have also reviewed evidence that seems more in line with the second, in that when well-known words are used in such studies, even fourteen-to-fifteen-month-olds respond to place and voice switches. How do the writers determine what is a 'well-known' word? Is it solely on the basis of what parents report? From: Junko Davis This study suggests that the place-of-articulation and voicing contrasts are partially integrated into the phonological system in the early stage of language development when the contrasts have not yet been fully acquired, and the maintenance of the contrasts seems to be influenced by the processing demands. Actually, I don't quite understand the phonological parse described in Tables (1) to (4) in pp. 397-398. Also, it seems somewhat counterintuitive to me that the phonological contrasts can be lost due to the processing demands. From: Fangfang Li This study focuses on the perceptual acquisition of 14-month olds, by doing three experiments of word-learning tasks on contrasts of place of articulation and voicing and the combination of the two in minimal pairs. The results show that 14-month old pay attention to none of the contrasts listed above. together with the fact that babies of similar ages can recognize the contrasts in familiar words, they concluded that perceptual acquisition is gradual and in a way paralell to production. comment: another way of stating their interpretation on the two sets of results would be the effect of frequency. the more exposure to a contrast, the more salient it would be in the child's perceptual system. so word-learning task would be an extreme case of 0 frequency word, whereas familiar words represent more frequent exposure. this also reminds me of Susan Nittrouer's developmental weight shift in speech perception, which basically saying that children start off by paying more attention to the transition of the segment and then shift to more segment/feature-oriented perspective. so maybe it is not "developmental shift", but rather a shift that takes place with more experience of the contrast. From: Kirk Baker p. 384 As per finding that <6MO infants distinguish contrasts. Does it make sense to say they don't process the stimuli as language, same as adults can make acoustic discrimination speech waveform processed as non-language? Do infants get the V[flap]V-V[d]V distinction? p. 385 PHONETIC means ACOUSTIC discrimination? p.396 Phonetic parse refers to perceptual parse by listener? My ears hear [bi] and my brain hears [di]? And OT constraints operate between these? Does their methodology really address the question? Do kids even understand this as word-learning task? Could they do it if talker's face is visible? Could they do it with real talker intending for them to learn contrast for real objects? From: ejkong@ling.ohio-state.edu This study tested infants' ability to perceptually contrast the place of articualtion and the voicing in a word-learning process of a phonologically legal monosyllabic word starting with a labial stop consonant. They found out that 14 mth-old infants are not discriminating stop consonants differnt in the place/voicing or thier combinations, when they are in the process of associating sounds with meanings. Infants' failures are attributed to the processing load of the task, which affects possible rankings between markedness contraints and faithfulness constraints. - It seems to me that the findings in this study are reflecting the nature of word-learning process that infants are likely to do, that is the abstractions over acoustically variable tokens with the same meaning. Infants' failure to contrast the place/voicing might indicate that they are still at the stage of collecting samples for the abstraction, being tolerant to the acoutic variations. In contrast, in the word-recognition task, infants are able to detact the switch of tokens, because they are kind of done with the signal abstractions and the switched token is not fit into thier abstracted signal. Questions: - Does the habituation phrase in the experiment necessarily ensure that infants didn't take the stops with place/voicing contrasts as homophones? - I don't quite understand the relationship between the ranking of faithfulness constraints and the degree of attention; "A higher degree of attention leads to higher ranking of faithfulness constratins" (p397). Didn't they say that the word-learning task requires more cognitive load (attention) than the word-recognition task? Then, aren't infants supposed to rank a faithfulness constraint higher when they learn words than when they recognize them, which is the opposite result from the present one? From: nagar@ling.ohio-state.edu The paper discusses experiments by way of which the authors prove that children by the age of 14 months do not have a distinction in there speech or perception between voiced/voiceless and place of articulation. The important point that authors make in this article is regarding the difference in the perception of sounds and production of sounds and the relationship of these to the meaning that the child attaches to the lexical items and sounds. The sounds that the authors concentrate on are [bi] and [di] and the voicing and place contrast between these sounds. From: HELENA RIHA p. 385 "One might conclude that when meaningful words are first acquired, lexical representations encode all segmental contrasts." It may be the case that certain segments are encoded in particular combinations rather than individually. It may be that the child only later parses the word into its segments and realizes that those segments occur in other words and in other positions. This makes me think of how I used to learn words in Mandarin during my early stages of contact with the language. I memorized compounds (and idioms) as a whole and only later noticed that their constituent morphemes appeared in other words and idioms. It was much more difficult to learn individual morphemes in isolation and then build up to words that contained them. p. 385 "This body of work continues to support the general view that some contrasts are acquired before others, and that there are therefore restrictions on the complexity of early representations." This seems to support Rice & Avery?s learning path model and the acquisition of contrasts as they are needed. p. 386 "By 17 months, when their vocabulary reaches a sufficient size, infants are able to associate a place-of-articulation difference with a difference in meaning." This indicates that children need to acquire a basic vocabulary before phonological contrasts become meaningful in perception. By comparing and contrasting new words with those that are already in their vocabulary, phonological contrasts become useful and relevant. p. 389 "A potential concern does arise from the fact that the forms [bI] and [dI] used in these experiments are actually ill-formed as English words." Isn't this a major oversight on the part of the experimenters? The children were probably sensitive to this constraint. They may have felt they were hearing syllables rather than words. p. 392 "We can conclude that the infants had difficulty with these words not because they violated English phonotactics but because they differed only in consonantal place of articulation." I can't help but wonder whether the artificial nature of the experimental task also limited children's performance. In normal parent-child interaction, words are embedded in sentences, and there is a clear communicative context, a reason to be distinguishing "bins" and "dins." Moreover, if children learn these words together from another person (rather than discovering them on their own), the other person would likely emphasize the difference between the words (e.g., Look, Chris! This is a *B*in, and this is a *D*in) and would probably encourage the child to repeat the words. Having the words embedded in sentences and acquiring them in a meaningful discourse context may affect success in perception and word learning generally. p. 399 "We find evidence (supporting that) 14-month olds do not respond to a switch in consonantal place or voicing when engaged in a word-learning task. However, when well-known words are used in such studies, even 14- to 15-month olds respond to place and voice switches." Is this evidence is really contradictory? Both findings support the idea that phonological contrasts are acquired gradually. In acquiring new words, 14-month olds do not respond to changes in feature contrasts because they are not yet familiar with the words and can only recognize them at a gross level (as some kind of nebulous whole). In well-known words, the same children respond to feature contrasts because they are familiar with the words and can perceive their finer distinctions. Their experience with the words enables them to tune into more fine-grained features of the words.