«DOCUMENT RESUME ED 363 732 CE 064 960 AUTHOR Fowler, Anne E.; Scarborough, Hollis S. TITLE Should Reading-Disabled Adults Be Distinguished from Other ...»
However, Gough (1983) pointed out that, even under ideal conditions, the context rarely determines absolutely what a word will be but only narrows the pool of possible words. He estimated that the predictability of content words (such as nouns and verbs) is only about 10% and the predictability of function words (such as articles and prepositions) is only about 40%. It is perhaps not surprising, therefore, that relying on such inexact cues to a word's identity is more characteristic of novice readers than expert readers. In fact, the greater a reader's level of skill, the less it appears that contextual cues are used, except in particularly difficult situations, such as when reading material is presented especially slowly or in a degraded form (Adams, 1990; Gough, 1983;
NATIONAL CENTER ON ADULT LITERACY 23Perfetti, 1985; Stanovich, 1980). The eye movements of novice and skilled readers are consistent with this apparent change in the role of context as a function of skill; that is, it is the most proficient readers who look, albeit very briefly, at every word, and the least skilled who explore the text less systematically (Rayner & Pollatsek, 1987). In short, the use of context as an aid to word recognition is one kind of interaction between the main components of reading, but this interactive effect appears to be most important for less skilled readers.
A more powerful influence on the accuracy and efficiency of word recognition is familiarity, practice, and instruction in identifying particular words. Simply put, words that an individual has read before are read more easily and more quickly than words that are encountered for the first time. More generally, words that occur with high frequency in text tend to be recognized more quickly than words of lower frequency. (For reviews of this research, see Adams, 1990; Carr & Pollatsek, 1985; Seidenberg & McClelland, 1989). Prior experience and familiarity are particularly important for the recognition of irregular or exception words, whose pronunciations cannot be decoded simply by applying letter-sound correspondence rules. In English, there are many such words that young children must learn to recognize simply on sight (e.g., of, laugh, who). With regard to achieving automaticity, furthermore, it is clear that the speed and accuracy with which words can be identified increases with practice and lays the foundation for skilled reading comprehension.
Although contextual cues and word familiarity facilitate word recognition, the most powerful influence on the identification of printed words is undeniably the ability to decode according to systematic correspondences between letters and sounds. For both skilled and beginning readers, it is only by decoding that one can potentially determine the identity of a word that has not previously been read, and hence for which no memorized image of its printed form exists. As Gough and Hi Binger (1980) stated, learning to decode is an important step for beginning readers because their
major task is:
....accessing tbe mental lexicon for known words that have never before been seen in print. If the novice can derive appropriate phonological representations for sucb novel printed inputs, then a lexicon already accessible on the basis of phonological codes through the course of language acquisition, can also begin to be accessed on tbe basis of print. (p. 131) TECHNICAL REPORT TR93-7 From the start, children are continually expected to read a great many new words; in fact, it is estimated that approximately 35% to 45% of the words in elementary school reading books appear only once (Jorm & Share, 1983). Also, while the identification of known words can, in principle, be achieved instead via sight recognition of a memorized visual pattern, there appear to be limits to the utility of relying exclusively on memorization of individual worcis (other than irregular forms). It is generally estimated that a child can acquire up to a fourth-grade reading vocabulary without decoding, but that progress beyond that level depends crucially on decoding skills. At all ages, it should be noted, the ability to decode pseudowordsto which previous lexical knowledge cannot be brought to bearis very highly correlated (typically 85% to 95%) with the ability to read real words.
The evidence that knowledge of letter-sound correspondences is crucially related to successful reading acquisition is overwhelming at this point, and several comprehensive reviews of this material are available (see Adams, 1990; Tunmer & Hoover, 1992). Of particular interest are several longitudinal studies. Jorm, Share, Maclean, and Matthews (1986) found that first graders with greater phonological decoding abilities later attained higher levels of reading achievement than children with a weaker grasp of lettersound correspondences who were similar in many other important respects, such as sight word vocabulary, verbal intelligence, gender, and schooling. Juel (1988), who studied a large sample of children from disadvantaged backgrounds, also found a strong relationship between decoding abilities in the first grade and later reading skills. Gough and Walsh (1991) noted that higher levels of pseudoword decoding skill led to faster acquisition of irregular as well as regular words. In short, the road to successful reading begins with a grasp of the relationship between printed letters and spoken sounds, and the application of that knowledge to the decoding of written material.
3. PHONOLOGICAL ANALYSIS OF SPEECH AND PHONOLOGICAL
DECODING OF PRINTTo understand fully the constellation of skills that must be acquired in learning to read, an examination is needed of what underlies decoding itself. As noted earlier, decoding involves the mapping of letters onto phonemes, the sound elements that make up spoken words. It is important to note it is only for alphabetic writing systems (like that for English) that phoneme-grapheme correspondences are the fundamental basis for word recognition;
NATIONAL CENTER ON ADUCVLITERACY 25in some languages, graphic symbols stand for syllables, morphemes, or entire words. It is also important to mention that reading acquisition is very different in many respects from oral language acquisition. Spoken language is acquired successfully and relatively effortlessly starting from an early age by nearly every child around the world. Literacy, in contrast, is not a universal aspect of human culture, is rarely learned before age five, almost always requires explicit instruction and deliberate effort, and is mastered with varying degrees of success by different children.
Furthermore, it is clear that an appreciation of the fact that spoken words consist of sequences of smaller sounds is not something that children ordinarily develop just from their experience with spoken language. In short, alphabet literacy is not a naturally developing human faculty, but rather one that was invented by humans and one that requires the unnatural facility to analyze spoken words into phonemes. It is this aspect of phonological processing that is crucial to decoding, and thus poses the greatest initial challenge for the beginning reader.
What makes phonological analysis so unnatural and difficult?
Most adults are so used to thinking that the letters of the alphabet stand for the sounds of speech that they fail to remember that this is actually not readily apparent. In fact, those sounds are embedded in a very complex speech stream that, for the child, is not immediately accessible to conscious analysis. Many phonemes cannot actually be heard or pronounced in isolation; for instance, try to say just the first sound in too without any vocalic element following it. Acoustic analyses indicate that it is impossible to isolate just the consonantal portion from the following vowel without making it unrecognizable. What is left turns out to be a chirp that sounds not at all like language. Not only is the speech stream not readily segmentable into a string of phonemes, but the acoustic characteristics of phonemes vary considerably depending on the context in which the phoneme occurs. For instance, the sound of the first phonemes of too and top are rather different to the ear; it is the brain that analyzes this complex information to recognize that the same phoneme has been produced. For a fuller introduction to these issues, reviews are available by Gleitman and Rozin (1977), and Liberman, Shankweiler, and Liberman (1989).
Becoming proficient at producing and listening to oral language does not require any conscious analysis of the phonemic structures of spoken words. Learning to read, however, does require this metalinguistic skill, which is often termed phoneme awareness.
Not until the child achieves the insight that words are composed of phonemic units can the child understand what letters actually TECHNICAL REPORT T193-7 stand for, and hence grasp the regular correspondence between letters and sounds. A great deal of research in the past two decades has demonstrated that preschool children lack full phoneme awareness and that differences among children in their metalinguistic understanding of phonological structure are related to their acquisition of decoding skills in the process of learning to read. For example, Liberman, Shankweiler, Fischer, and Carter (1974) showed that most 5-year-olds are unable to tell you that there are three sounds in the word cat, but that about half of all 6year-olds and nearly all 7-year-olds are able to do so. Similarly, there are marked increases with age from late preschool into grade school in metalinguistic abilities, such as judging whether two words begin with the same sound, categorizing words according to phonemic similarity, pronouncing a word without its first phoneme, and so forth. Moreover, there is abundant evidence that children's early reading abilities are reliably related to individual differences in phonological awareness skill. Correlations between achievement scores and metaphonological abilities have ranged from about 35% to 65% across studies, and are typically among the strongest predictors of reading achievement (Stanovich, Cunningham, & Cramer, 1984; Yopp, 1988; Wagner, 1988).
Although it was originally conceived that this metalinguistic insight preceded and permitted alphabetic literacy, several studies have suggested that phoneme awareness is sufficiently unnatural that it does not ordinarily develop unless the child has some experience with an alphabetic writing system. For example, very weak phonological analysis skills were seen among illiterate members of a Portuguese community who had not been exposed to written language (Morais, Cary, Alegria, & Bertelson, 1979) and among educated readers of nonalphabetic written languages such as Chinese (Read, Zhang, Nie, & Ding, 1986). Further research has indicated that the achievement of alphabetic literacy and of
phonemic awareness go hand in hand in a bi-directional process:
learning letters promotes linguistic analysis, which allows for letters to make sense, which leads to further phonemic analysis, and so on (Bowey & Francis, 1991; Juel, 1988; Perfetti, Beck, Bell & Hughes, 1987). A particularly interesting demonstration of this interaction was a large-scale study of disadvantaged first graders which indicated that although phonics was the most effective form of reading instruction, even this approach was effective only when the child began the year with an underlying grasp of phoneme awareness (Juel, Griffith, & Gough, 1986). Careful longitudinal studies suggest that, under normal circumstances, between the ages of about two and six years of age, children first become aware that words contain larger sub-units than the phoneme (e.g., such that
NATIONAL CENTER ON ADULT LITERACY 27rhyming relations, based on the identity of the entire end portions of words, can be appreciated), then become able to isolate phonemic onsets, and finally achieve full phonemic segmentation across all portions of words (Fowler, 1991).
The process of acquiring a general awareness of the phonological structure of words is probably initiated in the course of language play (Mann, 1991), but fine-grained phonemic segmentation is most likely to be the result of orthographic contact (Bradley & Bryant, 1983; Bowey & Francis, 1991). Acquisition does not appear to be constrained by any biologically sensitive period, insofar as adults have been shown to develop phoneme awareness upon exposure to an alphabetic written language (Morais et al., 1979; Read et aL, 1986). Several studies have also demonstrated that phonological analysis is a trainable skill in childhood as well. With appropriate and systematic instruction, considerable improvement has been seen in many children who lack phoneme awareness at school entry, and such training has led to demonstrable gains in later decoding skill compared to children who do not receive such training (Ball & Blachman, 1991; Bradley & Bryant, 1983; Lundberg, Frost, & Petersen, 1988). Finally, it should be noted that phoneme awareness is not an all-or-nothing phenomenon; long after the beginning reader is able to segment cat into its three components, he or she may still lack conscious access to the phonemic structure of catastropbe. In short, both phonemic awareness and decoding skills gradually improve during the course of learning to become a skilled reader.