Language: The Control of Perception

Joel B. Judd
Adams State College
208 Edgemont Boulevard
Alamosa, CO  81102
for consideration in the
Festschrift for
William T. Powers

    It may only be a slight exaggeration to claim that the linguistic Holy Grail consists of explaining the connections between brain functioning and language.  In other words, a theory of human communication is an extension of our efforts to explain brain and behavior. If this is the case our beliefs about the brain should have direct implications for our characterization of language, and vice versa.  With apologies for co-opting the title of Powers’ seminal book, I suggest the most promising theory addressing the brain-language connection is Hierarchical Perceptual Control Theory (HPCT).

    A recent summary of sociolinguistics (Coulmas, 2001) also frames the real question for linguistics:

How is it that language can fulfill the function of communication despite variation?

    Powers’ insight was to emphasize the role of behavior in perceptual control.  Likewise, the key starting point for linguistics is to observe that language is just as purposeful as other behaviors.  One might argue it is the purposeful behavior, for it is quintessentially human.  Language forms the basis for most of our complex interactions with family, friends, colleagues and others.  It allows for the possibility of resolving disputes and conflicts without resorting to violence.  Although Coulmas’ statement refers primarily to the way languages change over time, it also defines the HPCT perspective.  From phonemes to syntax, all aspects of individual linguistic behavior—whether written, signed, or spoken—constantly vary, yet we manage in most instances to communicate sufficiently well with those around us to accomplish our day-to-day purposes.

    As with other behaviors, the fact that our linguistic behavior varies is not a new discovery.  Especially after 1900, the means to document individual linguistic variability increased along with measurement technology.  For example, Pillsbury and Meader (1928) conducted a small study among colleagues on the musculature involved in speech production and noticed that phonemes constantly vary.  Their conclusion: “It may be seriously questioned whether one ever makes the same group of speech movements twice in a lifetime.  If one does, the fact is to be attributed to chance rather than law” (p. 218).

    Again in parallel with behavior generally, linguistic variability at the phonemic level doesn’t usually impact our ability to communicate.  However, “higher” level variability in morphology and syntax may be crucial, even life-threatening (What did you call me?!).  Linguistics, though, has done little beyond describing (or in some cases ignoring) such variability.  In other words, most research has relied on attempts to tie observable—or measurable—language behavior to either environmental contexts or presumed cognitive faculties.  This has been the source of fundamental problems for much of linguistic research, both from a behaviorist and cognitivist standpoint.  As Stanley Sapon pointed out over 30 years ago, “…if we take as our only data the formal properties of an utterance, then the only predictions we can make are predictions of form, not of substance” (Sapon, 1971).

    Sapon is alluding to the research pitfall of relying on descriptions of observable behavior in order to predict future behavior (or explain it).  For example, attempts to predict exactly which member of the class of words called ‘noun’ will finish a sentence like “What I really like to eat in Summer is ________” have failed.  As a result, some researchers have labeled such prediction “trivial.”  However, Sapon finds it disingenuous for scientists—and in particular linguists—to

…describe [as trivial] the specific predictions which ordinary, unenlightened people are wont to consider crucial.  I, for one, look with compassion upon the craftsman who does not know how to produce estimable work and settles instead for esteeming the kind of work he can do. (p. 77)

    What HPCT offers is a recast of the important questions about individual linguistic behavior, how it might develop and function.  If there is a hierarchy to perception in general, then the same principles should apply to language as well.  If behavior is the control of perception, then linguistic behavior is the control of perception as well. 

A Perceptual Control Hierarchy for Language

The following hierarchy is after Powers (1973, 1989) and Judd (1992). 
Applicable linguistic concepts are assoc iated with the appropriate level.


Level #

Perceptual Level

Type of Perceptual Control

Linguistic Equivalents





Coherent grouping of principles (‘citizen’; ‘religious’; ‘family’)

One’s language “identity”; code-switching in bilinguals; language variation (Coulmas, 2001); socio-cultural aspects



“Meta-awareness” (thoughts about thoughts); usefulness of programs; guiding ideas (‘honesty’; ‘politeness’)

Pragmatics and usage; language proficiency or aptitude; “prototypes” (e.g., Competition Model)



“If-then” decisions from lower levels (perceptual, not behavioral)

Self correction using explicit rules: 3rd-person singular -s, ‘i’ before ‘e’; Krashen’s Monitor (Krashen, 1985)



Perceived order of events (‘beginning’ à ‘end’)

Syntactic ordering of lexical items; description [ordering] of visual episodes (Tomlin, 1987)



Grouping, naming, etc. of experiences

Naming (objects, concepts, parts of speech); semantics



Connections among events (causation)

Ordering of “arguments” (e.g., “slots”, MacWhinney, 1987)





Wholeness of an activity; a “familiar pattern in time” (symphony)

Lexemes (words); idiomatic phrases



Change over time (a 5th to major 7th)

Intonation; stress-timed vs. syllable-timed languages



Unitary, recognizable arrangements (musical chords)

Letters or characters; syllables; phonemes (though see Kaye, 1989)



Sound quality (pitch); alignment; edge, contrast




Loudness; brightness; pressure [1st order systems-only direct contact with outside world]


    The preceding chart outlines some of the more self-evident connections between proposed hierarchical levels of perception and their linguistic equivalents.  If nothing else it should be clear that HPCT paints a picture of language that goes beyond the traditional phonology/morphology/syntax/pragmatics breakdown.  It also offers a structural basis for some kind of modularity (though probably not the innate modularism of Fodor), as Powers has argued:

. . . the division into levels and the subdivision of levels into independent control systems means that there is modularity at all levels:  each level consists of general-purpose control systems of a given type, available for an infinite variety of uses by whatever systems you want to add at the next level.  This makes sense in design terms, and in terms of development, evolutionary or within one lifetime.  If you want to build a self-organizing robot, make the system modular; that is, hierarchical. (Powers, CSGnet, November 8, 1991)

    The remainder of this discussion will offer a few examples that seem to evidence a good fit between HPCT and language.

    Our point of departure is the grouping of perceptual levels into “subjective” and “physical” reality.  Not only does this distinction make sense in general but particularly for language and language development.  There is growing evidence for similarities in the development of “lower-level” perceptions across languages.  The kinds of abilities referred to include sensitivity to the same kinds of temporal and spatial relationships defined by the configuration, transition, and event levels of perception (e.g., Petitto, 2000).

    As for the levels included in subjective reality, HPCT offers insights into language learning, linguistic variation, and other sociolinguistic and pragmatic questions such as: Why do men and women use language differently [gender differences]?  Does our language shape the way we think, or does the way we think shape our language [linguistic relativism]?  How does language serve to mark membership and identity [social class]?  Why might some people have a “knack” for learning language while others struggle [aptitude]?  What is the most effective way to learn another language [pedagogy]?

    In the area of second language acquisition and learning, HPCT may answer, or offer more satisfying explanations for, questionable distinctions and characterizations such as whether there is a difference between “learning” and “acquisition,” or between “instrumental” and “integrative” motivation; if there really are “compound” and “coordinate” bilinguals; or what “fossilization” really means.

    These questions are of course tied to the fact that as perception becomes more complex—as we move “up” the hierarchy—it also becomes more idiosyncratic and more subjective.  Many are the cortical stimulation studies which localize the same perceptions involved in somatic and propio-receptive behaviors across people (toe movement, vocalization, temperature sensation), few if any are the ones which find higher levels of perception (words, numerical calculation) in the same places across people (e.g., Ojemann and Whitaker, 1978 in the case of bilinguals).  As a result, HPCT implies a different research perspective for much of linguistics—one that takes a “specimen” approach (Runkel, 1990) rather than one which continues to rely on recording and tallying behavioral snapshots.

    All things considered, there doesn’t seem to be any good reason to propose a separate hierarchy for language.  While language is a kind of perceptual experience, perhaps the most important kind for humans as social beings, it is certainly not the only or even always the most effective type of experience.  At both extremes of the perceptual hierarchy there are what might be called “a-linguistic” perceptual levels.  At the initial levels, first-order systems for language perception are not any different than those for any other perception.  Intensities are intensities, whether they will be eventually be perceived as "language" makes no difference.  At the other extreme, the fact that we have difficulty putting into words concepts such as ‘love’ or defining terms such as ‘patriotism’ fits nicely with the idea that language is a means to an end.  With it we can act to control our perceptions, but ultimately it is not the only way we perceive ourselves or the world around us. 

Development and Foundation of Language

    Any discussion of language acquisition includes some discussion of philosophy as well.  This arises from the tendency of linguists (and applied linguists, and teachers) to speak of the ‘mind,’ while biologists, neurologists and others speak of the ‘brain.’  As a result, some have postulated linguistic constructs (e.g., ‘tense’ or “parameters”) that may have little connection to neurophysiological reality.

    There is in consequence a kind of dualism in language studies.  Jacobs (1988), in his discussion of language acquisition, points out,  "[D]ualistic thought on such matters is unjustified:  physiological states and mental states of the brain, incomprehensible as both may be, are one and the same . . . all learning involves anatomical/physiological alteration of neural substrate" (p. 306).  From a philosophical perspective, Bunge (1986) speaks of this same dualism when he says that ". . . the spinning of speculative hypotheses concerning immaterial 'mental structures' has taken the place of serious theorizing and experimenting on the linguistic abilities and disabilities of living brains" (p. 229), [emphasis added].

    In support of a unitary approach to language study (that is, one which avoids theorizing about mental structures that violate known neurological principles), some have begun to see principles of perceptual control in language.  Phonology again provides an example.  In HPCT the brain begins to distinguish printed or spoken language from other perceptions at the configuration level.  The quality of the perception doesn’t matter as much as recognizing that it is “language” and not some other kind of visual or aural perception.  As with, say, a musical chord, phonemes can be recognized whether a high, squeaky voice or a deep booming one produces them.  So while the traditional linguistic definition of phonemes as "basic units of speech" seems to be appropriate, there is still something missing.

    Perhaps this is why some have challenged traditional conceptualizations.  Kaye (1989) has said, "The phoneme is dead" (p. 154).  His claim stems from consideration of questions such as: how does one determine what a phoneme is?  Feature-based definitions become impractical when one considers how phonemes appear in spoken language (recall Pillsbury and Meader’s observations).  In short, many phoneticians are adopting approaches to phonology that deal with principles of phonological elements and their combinatorial possibilities and variations (Kaye, 1989, p. 164).  Such developments would support Powers's description of configuration perceptions.

    Viewing phonology as part of a hierarchy of perceptual control can account for another problematic phonological entity, diphthongs.  While a diphthong may at first glance appear to require perception of transition (and perhaps developmentally children initially perceive them that way), it is categorized as phoneme, at least in English (Mackay, 1987).  This is because its sound contrasts meaningfully with other sounds.  English-speaking adults are generally completely unaware that the [ai] vowel sound in a word like ‘high’ is a diphthong since it is perceived as a single phone.

    Insights into other aspects of early language development also corroborate implications of HPCT.  Infants begin to perceive key phonemic distinctions within a matter of weeks after being born (Molfese, 1977; Molfese et al., 1983), and children in a monolingual environment settle on their language's repertoire of sounds before a year has passed (Kuhl, Williams, Lacerda, Stevens & Lindblom, 1991).  Interestingly, though perhaps not surprisingly, Mack (1989) showed that children raised in a bilingual environment develop a "middle ground" for their production of similar phonemes in their two languages, thus simplifying the neurological load as well as satisfying reference levels—perhaps the PCT equivalent of killing two birds with one phone!

    Any discussion of development also raises the question of critical periods: is there one or more such periods for human language?  Strictly speaking, a biological critical period by definition requires that an organism have certain experiences within a particular temporal window or else key perceptions or behaviors never emerge (e.g., birdsong).  This is the strong form of the hypothesis.  Because such a clear-cut case for human language has never been documented (and it would be slightly unethical to artificially create one), weaker versions of this hypothesis—“sensitive” periods—are proposed for language (Snow, 1987).

    Part of the reason there is no all-or-nothing evidence no doubt stems from the fact that human language is complex, and becomes even more so if viewed in light of HPCT.  A true critical period for “language” would involve virtually the entire brain!  An alternative would be to propose multiple critical or sensitive periods: one for configuration-related perceptual development, another for transition-related perceptual development, and so on.  While again there is no definitive evidence for even this kind of perspective, there is some evidence of the need for early interaction with certain fundamental components of language.

    One of the most obvious results of someone learning a language after childhood (non-native or “L2” learning) is an accent.  Enough formal and anecdotal evidence has accumulated over the years to claim that the likelihood of having an accent in a L2 increases rapidly after about age five, and those individuals who learn a language after puberty almost never sound like “native” speakers.  Why is this the case?  One explanation could be that given the early timeframe for developing fundamental phonological perception and production, those who attempt to alter such perceptions later in life face the daunting task of modifying systems that have become automatized and subsumed into higher-level perceptions to the point where it is extremely difficult to access them again.  Furthermore, if the more mature (older) individual’s communicative needs (i.e., higher-level references) are met even with an accent, sounding like a native speaker may not be high priority.  Indeed, some interesting work has shown that certain accents are considered prestigious and may in fact be desirable!

Language and Subjective Perceptions

    What of higher-level, or subjective, linguistic perceptions?  HPCT offers just as provocative possibilities.  Some of Sapon’s concerns have born fruit as linguists and psychologists struggle to provide more than a descriptive account of language learning yet one that avoids the triviality he criticizes.

    Probably the main issue confronted by researchers is the logical problem of language acquisition.  This is the problem of overgeneralization, or the fact that children seem immune to [adult] attempts to correct their grammatical mistakes [1] .  Most well known linguists have promoted a search for some sort of innate constraint(s) on learning that allow a child to recover from overgeneralizing.  There is however at least one well-known alternative to the search for a “black box” and that is a model which fits nicely with PCT principles: the Competition Model (MacWhinney, 1987, 2001).  In contrast to the apparent either/or description of linguistic choices one finds in much research, close examination of language corpus reveal that children take a weighted approach to linguistic decisions.  That is, the acquisition of articulatory skills, vocabulary, semantic relationships, even grammatical roles are not neatly packaged, discrete choice mechanisms—one does not select his or her language components from environmental or genetic multiple choice databanks.  Instead, linguistic behaviors result from the interplay of various contextual and neurological factors, or in PCT terms, reference levels and disturbances to them.

    In fact, these abilities seem to fall more in line with “fuzzy logic” descriptions of decision-making.  A good example would be the development of linguistic “prototypes.”  Although the fact that we “learn” vocabulary and parts of speech gives the impression of finiteness to our linguistic knowledge, in reality that knowledge is fluid and variable.  The semantics for objects we drink out of, or for concepts such as ‘team,’ change as we gain relevant experiences.  In the same way, our [implicit] understanding of language grows and changes through our experiences.  These experiences help us develop prototypical examples and categories for grammatical relationships and other types of linguistic knowledge needed for effective communication.  They also form the basis for our decisions regarding such things as word choice (categories) or lexical ordering (sequence).

    Such a system would be more in line with our understanding of brain and neural functioning, and posits a view of language that reflects its functional nature (Bates & MacWhinney, 1989).  In fact, the implications of an HPCT perspective on language fits well with MacWhinney’s (1999) suggestion that the nature-nurture interaction be replaced with “emergentism”; that is, replacing models that stipulate “specific hard-wired neural circuitry” with “structures [that] emerge from the interaction of [biological and environmental] processes.

    Another but by no means final contribution of HPCT to understanding language involves the provocative nature of the “highest” levels of perception and their relationship with language and learning.  As already mentioned, a Perceptual Control Hierarchy for Language suggests that at both the lowest and highest levels our perceptions of the world diverge from mostly language-based perceptions.  It is important to realize that we can create a world of words that have little connection to personal (or “real world”) experience.  This danger was wonderfully described by Powers (1973):  

When that happens [failing to test symbol-manipulation against experience], word-manipulation carries them out over an empty abyss.  Words lead to other words, but all links with experience are left behind.  One can easily find himself chasing what may prove to be a ghost; what is the “real” meaning of intelligence or concept or vicarious meditation or quark?  (p. 166)

    Or in the case of language “aptitude” or “proficiency” and so on?  We need to be able to move beyond “word-manipulation” if we are to completely understand the connection between language and behavior.  HPCT offers perceptual control at a more overarching level than program or sequence.  These higher levels offer explanations for how influential our view of self is in our eventual attainment of language abilities.  The field of Second Language Acquisition (SLA) is a good source of tantalizing evidence.

    One popular notion in SLA is that of “fossilization”—the point(s) at which learners appear to cease progressing in their development of second language skills (Selinker, 1972).  As one might suspect, closer examination of individual subjects provides glimpses into higher-level perceptual control.  For example, Selinker (1972) cites a thesis by Kenneth Coulter that examined two Russian speakers learning English.  After investigating their failure to continue developing English language skills, Coulter concluded that some “strategy” lets learners know when they have “…enough of the L2 in order to communicate.  And they stop learning” (p. 217).  Another SLA researcher provided Selinker with personal commentary on learning strategies, suggesting that such strategies “…evolve whenever the learner realizes, either unconsciously or subconsciously, that he has no linguistic competence with regard to some aspect of the L2” (p. 219).

    Along these same lines, more recent work has focused on the strategies used by second language learners.  An interesting pair of students (Spanish-speakers learning English) observed by Abraham and Vann (1987) showed marked differences in the amount of time each employed key strategies (e.g., paraphrasing for understanding, repeating corrections) and how often they used such strategies.  The authors’ interpretation of their observations is revealing:

Gerardo appeared to take a broad view [of language]: his flexibility, variety of strategies, and concern with correctness suggest a belief that language learning requires attention to both function and form…In contrast, Pedro’s view of second language learning was relatively limited.  He appeared to think of language primarily as a set of words and seemed confident that if he could learn enough of them, he could somehow string them together to communicate.  The exact way they should be combined (and, indeed, the actual forms the words should take) was relatively unimportant.  Acting in accordance with this view, Pedro had adopted certain positive strategies that enabled him to be successful in unsophisticated oral communication…(p. 95, emphasis added)

    The italicized words suggest higher-level perceptual control that extends down through and influences many aspects of language ability.  It turned out that upon more detailed conversation with the two students Gerardo had aspirations of completing college and accepted the fact that effective, academic use of English was important to attaining this goal.  Pedro, on the other hand, had a narrow view of what he needed to know and was mostly interested in talking to girls on the beach.  Such revelations would make them excellent candidates for a version of “The Test,” though that is a topic outside the scope of this discussion.

    Finally, Tucker (1991) reported on adult immigrants to the U.S. and their progress in learning English.  One woman had emigrated to New York when she was in high school.  Her English writing was understandably poor—it lacked the expected elements of organization and grammar.  These faults persisted through school and two attempts at college.  However, in her third try at college suddenly this woman’s writing improved markedly.  In talking at length with her, Tucker found that since her last try at college she had divorced, gained insights into her own identity and abilities, and had developed professional goals for herself.  As with the two students above, it appears that with a marked change in her definition of concepts such as “independent” and “businesswoman,” this woman found that she could effect significant change in what had appeared to be static or “fossilized” language skills.

    The fact that such evidence fits well with HPCT encourages further investigation along these lines.  Who knows but what much of the tedious details involved in language learning would actually change if we simply understood better how learners ultimately see themselves?  And wouldn’t learning itself change when seen mainly as a question of whether learners perceive a discrepancy between where they “are” and where they “want to be”?

    This Big Picture view of language no doubt reflects a highly influential level of perceptual processing, one which deserves more attention.  As with other kinds of purposeful behavior, its effects have been noted for some time now.  Witness this observation, again from Pillsbury and Meader (1928):

When beginning to write, each stroke needs attention; when beginning to sew or crochet, each stitch; but with practice the vague intention to write a letter on a certain subject may be all that is necessary to take one to the typewriter in the other room and complete the writing. (p. 169, emphasis added)

    Later they offer an interesting summation of communicative purpose, “We are primarily interested in the effect we desire to produce upon the listener and so are usually not attentive to the processes by which we produce the effect” (p. 255).  Pillsbury and Meader are not alone; Dunkel (1948) concludes a chapter on speaking by suggesting:

… most of the time, “one thing leads to another” in speech and we end up by having said what we wanted to say.  We may have “purpose,” “volition,” “will,” “motive,” or what not.  Whatever this guiding force may be, we know little about it though it is the ultimate dictator of the whole process of speech.  (p. 60, emphasis added)

    The examples could go on, but the few given suggest a fruitful role for linguistic research from the perspective of HPCT.  The intent here was to point out some ways in which the principles of control theory, applied to language through a hierarchy of perceptual control, might lead to answers for key questions regarding language and language learning.  Certainly we are often skeptical when one theory looks to be an answer for everything.  But until something better comes along, HPCT promises a wealth of insights into the how and why of human language.

Works Cited

Abraham, R., & Vann, R.  (1987).  Strategies of two learners: A case study.  In A. Wendin and J. Rubin (Eds.) Learner strategies in language learning (pp. 85-102).  Englewood Cliffs, NJ: Prentice Hall.

Bates, E. & MacWhinney, B.  (1989).  Competition, variation and language learning.  In B. MacWhinney and E. Bates (Eds.) The crosslinguistic study of sentence processing. New York: Cambridge University Press.

Bunge, M.  (1986).  A philosopher looks at the current debate on language acquisition.  In I. Gopnick & M. Gopnick, (Eds.) From models to modules (pp. 229-239).  Norwood, NJ: Ablex Publishing Company.

Coulmas, F.  (2001).  Sociolinguistics.  In M. Arnoff & J. Ross-Miller (Eds.)  The Handbook of Linguistics (pp. 563-581). 

Dunkel, H.  (1948).  Second Language Learning.  Boston: Ginn.

Jacobs, B.  (1988).  Neurobiological differentiation of primary and secondary language acquisition.  Studies in Second Language Acquisition, 10, 303-337.

Judd, J.  (1992).  Second Language Acquisition as the Control of Non-primary Linguistic Perception: A Critique of Research and Theory.  Unpublished doctoral dissertation, Urbana, IL.

Kaye, J.  (1989).  Phonology.  Hillsdale, NJ: Lawrence Erlbaum.

Kuhl, P., Williams, K., Lacerda, F., Stevens, K., & Lindblom, B.  (1991).  Linguistic experience alters phonetic perception in infants by 6 months of age.  Science, 255, 606-608.

Mack, M.  (1989).  Consonant and vowel perception and production: Early English-French bilinguals and English monolinguals.  Perception and Psychophysics, 46(2), 187-200.

Mackay, I.  (1987).  Phonetics (2nd ed.).  Boston: Little, Brown and Co.

MacWhinney, B.  (1987).  The Competition Model.  In B. MacWhinney (Ed.).  Mechanisms of language acquisition (pp. 249-308).  Hillsdale, NJ: Erlbaum.

MacWhinney, B.  (1999).  The Emergence of Language (preface).  Mahwah, NJ: Lawrence Erlbaum.

MacWhinney, B.  (2001).  First Language Acquisition.  In M. Arnoff & J. Ross-Miller (Eds.).  The Handbook of Linguistics (pp. 466-487). 

Molfese, D.  (1977).  The ontogeny of cerebral asymmetry in man: Auditory evoked potentials to linguistic and non-linguistic stimuli.  In J. Desmedt (Ed.).  Progress in Clinical Neurophysiology, Vol. 3.  Basel: Karger.

Molfese, V., Molfese, D., & Parsons, C.  (1983).  Hemispheric processing of phonological information.  In N. Segalowitz (Ed.).  Language function and brain organization.  NY: Academic Press.

Ojemann, G. & Whitaker, H.  (1978).  The bilingual brain.  Archives of Neurology, 35, 409-412.

Pettito, L.  (2000).  On the biological foundations of human language.  In K. Emmorey and H. Lane (Eds.).  The signs of language revisited: An anthology in honor of Ursula Bellugi and Edward Klima.  Mahway, NJ: Lawrence Erlbaum.

Pillsbury, W. & Meader, C.  (1928).  The psychology of language.  NY: D. Appleton and Co.

Powers, W.T.  (1973).  Behavior: The control of perception.  Chicago: Aldine.

Powers, W.T.  (1989).  Living control systems.  Gravel Switch, KY: Control Systems Group.

Powers, W. T.  (1991).  CSGnet, November 8, 1991

Runkel, P.  (1990).  Casting nets and testing specimens.  NY: Praeger.

Sapon, S.  (1971).  On defining a response: A crucial problem in the analysis of verbal behavior.  In P. Pimsleur & T. Quinn (Eds.).  The psychology of second language learning  (pp. 75-86).  London: Cambridge University Press.

Selinker, L.  (1972).  Interlanguage.  IRAL, 10, 209-231.

Snow, C.  (1987).  Relevance of the notion of a critical period to language acquisition.  In M Bornstein (Ed.)  Sensitive periods in development: Interdisciplinary perspectives (pp. 183-209).  Hillsdale, NJ: Erlbaum.

Tucker, A.  (1991).  Decoding ESL.  NY: McGraw Hill.

[1] The logical problem of language acquisition involves both the fact that children utter language they do not hear from adults (e.g., they overgeneralize “goed” for “went”), as well as eventually conform their language to adult norms without corrective feedback.