Monday, February 14, 2011

(1987) The nature of phonological processing and its causal role in the acquisition of reading skills

(Wagner & Torgesen, 1987) Reviews literature on Causal role of Phonological Processing in Reading acquisition, covering:
  • Introductory review of phonological nature of reading (definitions, assumptions about level of language conveyed by printed word
  • Relations between acquisition of reading skills and phonological awareness, phonological recoding for lexical access, phonetic recoding to maintain information in working memory.
  • Consider hypotheses about the nature of phonological processing that emerge from examining interrelations among measures of different kinds of phonological processing.
  • Summarize the major empirical findings from review, identify gaps in current knowledge and issues to be resolved, propose how gaps in current knowledge and unresolved issues can be addressed

Phone (Greek) sound or voice
Speech = continuously variable waves of acoustic energy, imperceivable
Phonetic level – speech represented by individual phones
Perceived sound distinctions are phonemes, that is, a group of phones that speakers of a language consider to be variations on the same sound.
Allophones are the individual phones that make up a phoneme.
Morphophoneme meaning & sound are components of our writing system and orthography.
Our knowledge about words is represented in our lexicons by abstract strings of systematic phonemes. Families of words are related by meaning
Speech = using phonological rules to transform abstract phonemes into surface phones that relate to the articulatory gesture of speech.
Syllable is the smallest independent articulable segment of speech, or a unit of speech segmentation. Vowels require vocal tract open and vocal folds vibrating.
Consonants produced by constricting vocal tract. Opening & closing of tract = syllable (but imprecise rather than easily distinguished)
Phonological processing is the use of oral information, that is, the sounds of our language for transcribing and interpreting written communication.

The nature of phonological processing

The alphabetic system provides information about our language at the phonological level. Without an awareness of the phonological component of our language, reading is a difficult process.

Acquiring Reading Skills (Older studies)

English spellings are not associated with meaning like pictographs might be, but with phonemes. Consequently, beginning readers need to know that printed symbols represent units of speech and units of speech are represented by phonemes (Crowder, 1982). Learning symbols (e.g., environmental print) can be accomplished by severely disabled readers (Rozin, Poritzky, & Sotsky, 1971), but learning printed symbols represent systematic phonemes (phonological nature of our language) is taxing.

Without PA, the pattern of letter-sound correspondences is arbitrary (Mattingly, 1980). It is necessary for both segmenting letter strings of words and blending sounds to pronounce the word (whether meaningful or not).

A 1974 study by Liberman, Shankweiler, Fisher, and Carter found 4 yr olds couldn’t segment words by phonemes but half of them could by syllable;17% of 5s could segment by phoneme, and half by syllable; 70% of 6s could segment by phoneme and 90% by syllable. Similar results were found in 1972 study by Calfee, Chapman and Venezky. 5½  yr olds could produce a rhyme 39% of the time. Success at producing early rhymes was correlated with later success in reading.

The nature of the task appears to be the key to whether young children can demonstrate phonological awareness.  Fox and Routh (1975) found evidence that PA can develop before reading is taught. 3-6 yr olds listened to monosyllabic words, and asked to say just a little bit of the word. 3s could segment some words into beginning and ending sounds. By 5, they could segment first & remaining sounds for half the words.

Bradley and Bryant (1985) used a phoneme categorization task with 4s and 5s (like Sesame St: One of these words doesn't belong; for initial, medial and final sounds). A follow-up three yrs later (N=368) correlations were found between performance on the original categorization task and performance on standardized achievement tests in reading, spelling, and a math test as well as the sound categorization delayed test and the WISC (1974 ed.). With IQ and age as constants, wound categorization accounted for 4-10% of the variance in rdg., 6-8% in spelling and 1-4% in math. Sound categorization score showed significance at p= .001, suggesting PA in prereaders is a causal factor in sucess in early reading and spelling. Size of the group makes the results reliable.

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