Category Archives: Discussions

Problem set solution problems (and solutions)

Several months ago a helpful colleague contacted me about phonology problem set solution files that I had stupidly left on a public course website for all of Google-land to see. I immediately removed the files, and now I just hope that copies of them are not lurking about the interwebs. I didn’t really appreciate the depth of my stupidity until a few students recently had the gall to write to me (and in one case to my Department’s webmaster) to ask where all the solutions had gone! Anyway, I hereby apologize profusely to everyone for any bad consequences (past or future, known or unknown) that my stupid mistake may have had.

But to try to make some lemonade from these lemons: this experience has had me thinking about ways in which we phonology instructors might take advantage of the interwebs in order to share problem sets and their solutions amongst ourselves. Any ideas out there for how best to implement something like that? Obviously, it would have to be secure and there would need to be a gatekeeping process for access, but ideally it won’t just involve everyone sending email to each other. A private wiki or blog? An open-source course management system? Something else? Comments are open.

Meet, match, fit — what’s your poison?

I’ve been working a lot on stuff that requires me to write about strings that “X the structural description of” some rule, and in going back over what I’ve written I find that I alternate among three values of X: meet, match, and (much less often) fit. I’m most used to meet, but on some days I prefer match; Google fits my profile, with about 10 times as many hits for “meets the structural description of” than for “matches the structural description of” (though I haven’t expanded the search for other variations of the relevant lemmas and possible phrasings). What do you prefer to use, and why? I’d be curious to see. In the meantime, I’m changing all of my “match”-es to “meet”-s. Ah, consistency.

N. Hewlett (1990) Processes of development and production (Part 2)

Hewlett begins discussion of dual lexicon models with basic premise that, if children have accurate perception but inaccurate production, then “there is not just a single, modality-independent lexicon in which phonological representations are stored.” (p. 28) Hewlett lists several advantages to this basic framework. First, lexical avoidance (Schwartz & Leonard, 1982) is easily explained. Second, the “rules” like fronting and gliding that apply to child speech do not need to occur in real time. In many ways, this is helpful for explaining why the rules apply to environments, rather than to particular words. Exceptions abound, however! These exceptions include regressive idioms, where a child produces a word incorrectly even though similar words are generally produced correctly; and progressive idioms, where a child produces one word correctly when similar words are produced incorrectly. The problem with idioms is where Hewlett strikes out on his own, proposing a revised dual lexicon model.

It seems likely that reproducing the box-and-arrow model from the chapter would be a violation of copyright, so I will do my best to provide verbal descriptions for now. There are four four key boxes in the model (clockwise from upper left): the input lexicon, the output lexicon, a motor processor, and a motor programmer. The input lexicon is where incoming acoustic signals are matched to stored lexical items. Hewlett states explicitly that, “The input lexicon contains perceptual representations in terms of auditory-perceptual features.”

Realization rules link the input lexicon to the output lexicon, which contains articulatory representations. From there, an articulatory representation can be sent to the motor processor, where a motor plan is assembled using syllabic units. There is an alternative route, however, going through the motor programmer. If a realization rule does not exist, or if there is cause to eschew the realization rule, then the perceptual representation is sent to the motor programmer, where a motor representations is built from scratch. From there, it can either go directly to the motor processing component for implementation, or it can go to the output lexicon for storage, or probably both. Additional levels of production mechanism follow motor processing, including a segmental level of motor processing (which is acquired after the onset of speech), a motor execution level where muscle contractions are planned, and finally the signal sent to the vocal tract, representing the actual articulations.

How well does Hewlett’s model handle the data discussed in my last post? First, lexical avoidance is explained by postulating an entry in the input lexicon that has no corresponding motor plan (Hewlett is unclear here, but I think he means there is no corresponding entry in the output lexicon). Realization rules in which sound contrasts are neutralized (fronting, gliding, etc.) are the result of multiple input lexicon entries being mapped to the same output entry. Improvement in speech accuracy over time is handled by various forms of feedback, including the revision of output lexicon forms by passing input forms through the motor programmer.

There are many positive aspects of Hewlett’s model, and it does improve on the model proposed by Kiparsky and Menn (1977). However, the empirical coverage of the model is still quite limited. Here are a few examples. First, although Hewlett is careful to point out how important phonology is for explaining paradigmatic phonological rules, his model does not include a robust phonological grammar. The input and output lexicons are connected by an arrow, but this obscures what a difficult relationship this must be. How, for example, are output lexical items merged when they remain distinct in the input lexicon (e.g., when the words ‘rock’ and ‘walk’ are pronounced identically, or when /r/ and /w/ are pronounced identically, in general)? What mechanism is responsible for the merger? Notice that previous generative approaches are not helpful here because part of the challenge is to show how the input lexicon–including words like ‘rock’ and ‘walk’–links to the output lexicon–where ‘rock’ and ‘walk’ become merged. Grammars which do not split the lexicon into input and output components are therefore shielded from this problem. Progressive and regressive idioms are also unexplained by the single arrow between the input and output lexicons. The model has no way of explaining why some words might not follow an otherwise consistent grammatical pattern.

Second, how do articulatory representations develop? Consider who a child comes to produce their first word. Based on Hewlett’s model, we can reasonably assume that the child has an accurate perceptual representation of the word in their input lexicon. How is that word then matched up to any motor representation. Presumably, babbling plays some role in the developmental process, but this is not discussed outside of input from the motor programmer. We might look to work by Guenther to solve this problem (e.g., Guenther, 2006), but Hewlett leaves the process unspecified.

Finally, Lise Menn consistently mentions the important of explaining why speech accuracy improves during imitation, but Hewlett’s model is not specific enough to account for this fact.

Overall, Hewlett’s chapter provides an outstanding review of much of the work on child speech production and phonology up to 1990. His model offers several advances compared to similar models proposed by Menn (Kiparsky & Menn, 1977; Menn, 1983), but many facts about speech development remain unexplained.

N. Hewlett (1990) Processes of development and production (Part 1)

I’m following up on my review of Kiparsky and Menn (1977) with a review of Hewlett (1990), which extends the dual-lexicon model in several interesting ways, including a more detailed production component and an updated literature review. Unfortunately, the chapter is so long that it doesn’t really seem appropriate to review it all at once. In fact, this post will probably be too long. If you’d prefer shorter posts, let me know!



Hewlett reviews major findings in normal and disordered phonological/speech development, with the goal of motivating a model of early speech production building on previous work [1, 2]. The coverage in the manuscript is extensive, and the criticism is often very insightful. Below is a short description of the findings that Hewlett covers.

Hewlett begins his review with very early speech development, including babbling.* Babbled sounds are typically the same sounds in early words, and babbling usually overlaps with the first real word productions [3]. Relevant work not discussed by Hewlett include research from Boysson-Bardies and colleagues showing that babbling sounds are language dependent and even sounds that are common in babbling around the world often have language-specific phonetic characteristics [4, 5].

When word production begins in earnest, Hewlett argues that certain aspects of early speech are consistent. First, early ‘proto-words’ [6] are highly variable in their form. Thus, although the child’s production goal might be consistent—for example, they are always referring to ‘milk’—the form is entirely inconsistent. Second, early words are generally single words or unanalyzed phrases (the parts of the phrase don’t recombine).

Hewlett argues that a separate stage can be identified around 1;6 (years; months), which roughly corresponds to what is often called the ‘word spurt’. Hewlett further elaborates on phonological systematicity during early word production. Young children apply systematic patterns to their speech. These patterns might include consonant cluster reduction (‘snow’ is pronounced [no]), or application of a child-language-specific rewrite rule (/r/ à [w] word-initially and word-medially), or application of a prosodic template, such as a [CVjVC] template [7]. Hewlett writes, “The important implication of this is that the child’s pronunciation patterns exhibit regularities which yield to a systematic description within a phonological framework.” (p. 19) Thus, the enterprise of child phonology has been either to 1) describe the child’s phonological inventory, including contrasts and phonotactic restrictions, or 2) write rules that describe how children get from the adult form, which children are presumed to know based on their perceptual abilities. I will not go into great detail about these proposals, but Hewlett reviews well-known rules such as /r/ à [w]. Finally, although Hewlett discusses the issue later in the paper, this stage of phonological development includes many examples of ‘lexical avoidance’, or cases in which children avoid words with particular sounds [8].

At this point, Hewlett reviews models of phonological development, including proposals by Jakobson [9], Stampe [10], and Menn ([2]; the dual-lexicon model, also described in [1], which I reviewed in a previous posting). He then goes on to describe children’s perceptual abilities, which are generally agreed on to be quite good. And, of course, the explosion of the infant literature starting in the early 1990s confirms that infants are very good at learning linguistic/phonological patterns before they begin to speak.

As a sort of contrasting section to `phonological development’ as described above, Hewlett reviews `phonetic development’, in which he focuses on the measurement of speech production. Several findings are noteworthy. First, children’s speech is known to be more variable, including long durations for linguistic targets and greater variability. Regarding variability, recent work by my current mentor Lisa Goffman, and her collaborations with her mentor Anne Smith, have greatly added to our understanding of speech motor variability in children. Some examples: [11] showed that oral-motor stability is below adult levels even at 14 years of age. [12] showed that, contrary to what one might expect from a frequency-based explanation, native English speaking children and adults produce iambs with more stability compared to trochees.

Continuing with Hewlett’s discussion of phonetic development, children’s formants tend to be more variable than adult’s formants [13]. Hewlett discusses the issue of whether children show more or less coarticuation than adults. A number of researchers, Susan Nittrouer being one example [14], have claimed that children actually show greater amounts of coarticulation. The implication is that children have less segmentalized speech, and therefore their early speech consists of unanalyzed whole words. This claim has been hotly debated (or was hotly debated 20 years ago), but it appears that coarticulation is often just different in children [15], without there being either more or less coarticulation in child speech.

Hewlett also discusses the issue of `covert contrasts’ or `incomplete neutralization’—cases where children appear to be producing two sounds the same but are actually producing them distinctly. For example, both /r/ and /w/ might be realized as something like a [w], but in fact, the productions are distinct, and children can reliably identify which word they intended from their own productions [16]. Elsewhere, I have argued that this is a systemic problem with analyses of child phonology. Because so much of the literature on `phonological processes’ in child speech is based on transcription data, it is unclear whether these cases reflect phonological processes or covert contrasts (in which case, `phonological’ must mean something entirely different than what it is usually taken to mean).

Hewlett concludes his review of phonetic development with three findings. First, sounds that appear in babbling may disappear from a child’s sound inventory after the onset of word production. Second, although adults are very good at compensating for a bite block and hitting acoustic targets, children may be less good at this [17]. Third, Hewlett notes that children seem readily able to acquire a foreign accent as well as a foreign language (although some more recent work [18] suggests that accent acquisition generally falls on a continuum based on age of acquisition). Regarding the last two findings, Hewlett concludes that children must be better than adults at learning to produce new sounds.


[1] Kiparsky, P. & Menn, L. (1977). On the acquisition of phonology. In Language Learning and Thought, J. Macnamara (Ed.). New York: Academic Press.

[2] Menn, L. (1983). Development of articulatory, phonetic, and phonological capabilities In Language Production, Vol II, B Butterworth (Ed.). London: Academic Press

[3] Locke, J. L. (1983). Phonological Acquisition and Change. New York: Academic Press.

[4] Boysson-Bardies, B. d., Halle, P., Sagart, L., & Durand, C. (1989). A crosslinguistic investigation of vowel formants in babbling. Journal of Child Language, 16(1), 1-17.

[5] Boysson-Bardies, B. d., & Vihman, M. M. (1991). Adaptation to language: Evidence from babbling and first words in four languages. Language, 67(2), 297-319.

[6] Menyuk P. & Menn, L. (1979). Early strategies for the perception and production of words and sounds. In Language Acquisition, P. Fletcher, M. Garman (Eds.). Cambridge, UK: Cambridge University Press. pp. 49-70.

[7] Priestly, T. M. S. (1977). One idiosyncratic strategy in the acquisition of phonology. Journal of Child Language, 4, 45-66.

[8] Schwartz, R. G., & Leonard, L. B. (1982). Do children pick and choose? An examination of phonological selection and avoidance in early lexical acquisition. Journal of Child Language, 9, 319-336.

[9] Jakobson, R. (1968). Child Language, Aphasia and Phonological Universals. The Hague: Mouton.

[10] Stampe, D. (1969). The acquisition of phonetic representation. Papers from the 5th Rebional Meeting of the Chicago Linguistic Society, 443-454.

[11] Smith, A. & Zelaznik, H. (2004) Development of functional synergies for speech motor coordination in childhood and adolescence. Developmental Psychobiology, 45, 22-33.

[12] Goffman, L. (1999). Prosodic influences on speech production in children with specific language impairment and speech deficits: Kinematic, transcription, and acoustic evidence. Journal of Speech, Language, and Hearing Research, 42, 1499-1517.

[13] Eguchi, S. & Hirsch, I. (1969). Development of speech sounds in children. Acta Otolaryngology Supplement, 257.

[14] Nittrouer, S., Studdert-Kennedy, M., & McGowan, R. S. (1989). The emergence of phonetic segments: Evidence from the spectral structure of fricative-vowel syllables spoken by children and adults. Journal of Speech and Hearing Research, 32, 120-132.

[15] Goodell, E. W. & Studdert-Kennedy, M. (1993). Acoustic evidence for the development of gestural coordination in the speech of 2-year-olds: A longitudinal study. Journal of Speech and Hearing Research, 36, 707-727.

[16] Kornfeld, J. R., & Goehl. (1974). A new twist to an old observation: Kids know more than they say. Chicago, IL: Chicago Linguistic Society.

[17] Oller, D. K. & MacNeilage, P. F. (1983). Development of speech production: Perspectives from natural and perturbed speech. In The Production of Speeech, P. F. MacNeilage (Ed.). New York: Springer Verlag, pp. 91-108.

[18] Flege, J. E., Munro, M. J. & MacKay, I. (1995). Factors affecting degree of perceived foreign accent in a second language, Journal of the Acoustical Society of America, 97, 3125-3134.

Kiparsky and Menn (1977).

Kiparsky, Paul, and Menn, Lise. (1977). On the acquisition of phonology. In John Macnamara (Ed.), Perspectives in Neurolinguistics and psycholinguistics. New York, NY: Academic Press. pp. 47-78.

Kiparsky and Menn (hereafter KM) present a theoretical argument for children as active discoverers of grammar, building structural representations based on evidence from the ambient language. In the process, KM propose a dual lexicon. The split includes one path between phonetic and phonological forms (i.e., some phonological processes map acoustic forms to the underlying phonological representations that link related words) and another path between incoming phonetic forms and the phonetic output that children create.

The chapter begins with “The Learning of the Phonetic Repertoire”, a discussion of the two major proposals for child phonology that existed in 1977. The first was Roman Jakobson’s, who proposes that phonology develops according to a universal system of contrasts, and contrasts are learned by children in the order of most to least universal. For example, children should contrast /d/ and /g/ before they contrast /d/ and /b/ (pp. 48-49). The problem with Jakobson’s approach is that it says nothing about the order in which the sounds themselves will be acquired. Furthermore, the absence of a contrast may indicate that children are intentionally, or selectively, avoiding a particular sound, but Jakobson says nothing about this or why sound evasion should happen. Therefore, KM consider Jakobson’s theory to be difficult to falsify.

Stampe’s theory is specific about when sounds will be acquired, but makes a distinction between phonological rules and phonological processes. Rules are the grammatical means by which speakers convert from phonological to phonetic word forms, such as the flapping or homorganic nasal cluster rules. Processes, on the other hand, are innate rule-like conversions that explain the kinds of errors that children make. For example, children produce voiced word-final stops without voicing (/d/ –> [t]/__#) because of a devoicing process. Speakers of languages like English, which do voice final stops, must overcome these processes.

KM describe several problems with this view. First, it appears that Stampe’s theory requires children to learn phonological rules in the same order as they would unlearn phonological processes. This is an empirical but unstudied question.* Second, KM find no reason to assume that adult speakers maintain rules on the one hand and processes on the other (i.e., German speakers do not appear to be stuck in a word-final devoicing process, and regardless, they must still learn the allomorphy that relates allomorphs with voiced and voiceless final stops).

KM also criticize both Jakobson and Stampe as being overly deterministic and not allowing for the kind of variability inherent to child language learners. As evidence, they point to the fact that children break up consonant clusters in a variety of ways, and to the fact that children often produce phonological idioms, words that are produced more accurately than the phonological processes apparently at work in their language would predict. In sum, KM state that we need a new model of phonological development. However, they do not focus much on the development of sounds or sound contrasts. Instead, they focus on the fact that children’s production abilities lag behind their perceptual abilities.

KM propose the dual lexicon to account for a distinction between cognitive grammar learning and articulatory sound implementation. Children may learn the cognitive grammar at whatever pace (KM describe it as going on over many years, although I think that today’s infant literature would generally contradict that**), but the development of a productive sound repertoire is separate from the cognitive grammar. Thus, we have two lexicons.

The second part of the book, “The Learning of Morphophonemics”, is somewhat orthogonal to the dual lexicon proposal, so I do not discuss it.

Here, I identify what I think are outstanding issues in the paper, some of which will be addressed in future posts. First, is the dual lexicon meant to be only a description of the grammar, or is it also a processing model? In other words, when formulating a message, does a child start with the phonological grammar, which is translated into a phonetic form, which is then translated into the child’s pronunciation? KM suggest that, in fact, their may be yet another step, in which physical limitations act on the message, as would be the case for a lisp. Second, KM propose that children do not have allomorphy. Is this really true? It seems to me that children could be learning meanings and linking related word forms at a fairly early age. However, I’m not familiar with the literature on this topic. Third, the logical dependency of the dual lexicon and KM’s proposal of the child as “language discoverer”*** view is not clear to me.

The Dual Lexicon Model

Hello All,

I’ve lately become interested in the dual lexicon model, originally conceived of by Lisa Menn and put in print in Kiparsky and Menn (1977). My basic interest is in what I consider to be an outstanding problem in phonological development, and the primary motivator of the dual lexicon model, namely, why children’s production abilities lag behind their perceptual abilities.

To satisfy my interests, I’ve started reading more about the model and its various instantiations, and I’m posting my notes to Phonoloblog. In a moment, I’ll post a review of Kiparsky and Menn (1997). Future posts will cover Hewlett (1989), Menn and Matthei (1992), Smolensky (1996), and a section of Hale and Reiss (2008). If you’d like to see a particular manuscript reviewed, let me know. I’d also love to get feedback about the proposals I’m reviewing (or about my reviews). Thanks!


The House that Halle Built

…and we’re back. A couple of years ago, there was a lively discussion about phonological opacity that was split between Mr. Verb and phonoloblog. Mr. Verb has now posted a new installment — well, sort of. The post is mostly just a pointer to this MIT News piece on Morris Halle, but Mr. Verb references the earlier discussion (calling it the “Opacity Wars” in a later comment) and explicitly invites some reaction. This is mine.

(Before moving on, you may want to (re-)acquaint yourself with the earlier discussion, all the links to which can be found here. Mr. Verb says “start here and work back”, but that’s hardly helpful; the only link in that post is a totally useless one to phonoloblog‘s main page.)

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Opacity deconstructed

In the before time, in the long long ago, I had a little tête-à-tête(-à-bête-noire) about phonological opacity with Mr. Verb and friends — you can follow along (again, or for the first time) here, then here, then here and here and here and here, then back here, and finally ending here (and don’t forget to squeeze the comments).

I got very hot under the collar about various things during that discussion, so much so that the focus of the discussion kinda shifted to my frustration with anonymous commenters on the internets (even my good friend Ed played for the other team on that one). But there was just one thing I was really upset about: the apparent inability of many fans of rule ordering to say anything about the fact that blocking is an instance of opacity about which rule ordering has nothing to say. (I used nonderived environment blocking as an example, but any other forms of blocking work.) The curse of the true believer is an unwillingness or inability to question the claims of the belief system, and the relevant claim in this case is “rule ordering explains opacity”.

Well, I’ve just finished a paper (for the forthcoming Blackwell Companion to Phonology) that sets out the issues (as I see them, of course) in a more academic, less hot-headed format, and I’ve posted it here. I hope that it generates some discussion here, either in the comments below, in new posts, or even over on Mr. Verb’s blog.

Hold your theory still so I can stomp on it, OK?

I’m clearly not above fighting on the internets, even with folks who choose not to reveal their true identities while making flippant remarks about the vices and virtues of competing theoretical frameworks. I’m referring, of course, to the discussion with Mr. Verb & friends that I initiated here, with the remainder of the discussion on Mr. Verb’s blog (follow the links in the comments section of my post).

In the fourth part of his response, Mr. Verb correctly points out that I started the nastiness with this remark (emphasis added to the quoted “quip”):

In my view, it requires a lot of (willful) ignorance of a huge amount of important work in the 70s and 80s to think that OT doesn’t make significant progress in many areas (duplication, conspiracies, top-down and bottom-up effects, the emergence of the unmarked, …) where SPE essentially foundered.

And I’m the first to admit that I continued in the same nasty vein in the comments sections of Mr. Verb’s responses to my four challenges, with particular vitriol reserved for a certain “Cassaday Rassmussen” (who is doubtless an extraordinarily cute though cheeky little devil, much like the sea otters s/he loves so much). I was apparently inappropriately offended at Cassaday’s combination of willingness to be just as nasty as I was and unwillingness to be identified. (I am somehow less offended by Mr. Verb’s anonymity, given the clues he leaves here and there that help to narrow the field of possibilities down considerably.)

ANYWAY, now that Mr. Verb’s multi-part response to my multi-part challenge is over (save for an appendix that promises to tie up some loose ends), I figured it was an appropriate time to summarize some of my thoughts on the matter and the episode, beyond making rabid remarks in the comments area of an anonymous blog. Read on (and comment, anonymously or not!) if you’re interested, navigate away (to youtube, for example) if you’re not.

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What's a theory to do?

I don’t read Mr. Verb regularly, but I really should. On occasion, he’ll slip into a “moment of theoretical linguistic seriousness” of the kind that we (well, I) attempt to maintain consistently here at phonoloblog (ahem). Case in point: a post from a couple months ago on phonological opacity, following up on a reader’s questions about something mentioned in passing in this post. (Hat-tip to Ed.) The post on opacity concludes:

In any monostratal theory (one without stages of derivation), getting these interactions is a huge problem. This isn’t the place to run through them, but some readers will be familiar with sympathy theory, comparative markedness, and so on. I heard one person sum it up this way a few years ago:

Opacity is ubiquitous in human language, and earlier theories of phonology could deal with it easily. It’s hard to see why those advantages have been abandoned for an approach that can’t handle opacity without lots of gymnastics, if at all, for benefits that don’t look all that great.

(I’m pretty sure that it’s safe to assume that “earlier theories of phonology” refers to serial, rule-based generative phonology in the SPE-and-subsequent-developments sense, and that “any monostratal theory (one without stages of derivation)” and “an approach that can’t handle opacity without lots of gymnastics, if at all” refers to Optimality Theory. Correct me if I’m wrong.)

I’m not going to contest the ubiquitousness of opacity in human language claim, having recently written an article assuming this to be true (appeared in Phonology 24.2, 217-259). I’ll also assume that we can all agree on the legitimacy of at least some examples of opacity, in the sense that we agree that such cases involve the interaction of synchronic phonological processes (pace Sanders on ‘synchronic’ and Green on ‘phonological’). But I would like to challenge Mr. Verb (and the quoted summer-upper) to defend (some of) the remaining claims, explicit and implicit, made in what I’ve quoted above. Here is a list of what I take those claims to be.

  1. OT is by definition monostratal.
  2. OT requires “lots of gymnastics” to account for opacity, while SPE doesn’t.
  3. SPE(-and-subsequent-developments) “could deal with [opacity] easily”.
  4. The benefits of OT over SPE “don’t look all that great”.

More commentary on each of these below the fold.

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