Speech production The areas in the vocal tract where production of consonants takes place. Source: Payne, D.G. and Wenger, M.J, Cognitive Psychology. New York: Houghton Mifflin, 1998. Copyright © 1998 by Houghton Mifflin Company.

Some common speech errors Some people with damage to a specific part of the brain have an inability to produce speech, or they will produce meaningless speech. Speech errors or slips of the tongue, however, are not confined to those with brain damage. Some common speech production errors made by normal people are shown in this slide. Source: Adapted from Fromkin, V.A., Speech production, in J. Berko Gleason and N.B. Ratner (eds), Psycholinguistics. Fort Worth: Holt, Rinehart & Winston.

Fixations during reading The ovals in this slide are placed above the locations of the brief fixations that occur during reading; the numbers within the ovals indicate the durations of the fixations (in milliseconds). Arrows indicate backtracking to words already examined. (a) A good reader. (b) A poor reader. Source: Just, M.A. and Carpenter, P.A., The Psychology of Reading and Language Comprehension. © 1987 Pearson Education. After Buswell (1937). Reproduced with permission.

Examples of responses infants make to various speech sounds Some of the responses infants make to various types of speech sound. Source: Berko Gleason, J., The Development of Language (4th edition). Boston, MA: Allyn and Bacon, copyright © 1993 by Pearson Education, reprinted with permission.

The acquisition of inflections and function words by children This slide shows the approximate order in which children acquire some common inflections (affixes that are added to words, usually to alter their tense or number) and function words (words that convey little meaning but that are important in specifying a sentence’s grammatical structure). Source: Adapted from Clark, H.H. and Clark, E.V., Psychology and Language: An introduction to psycholinguistics, 1977. © 1977, reprinted with permission of Wadsworth, a division of Thomson Learning: www.thomsonrights.com, fax 800 730-2215.

Semantic relations comprehended by Kanzi, a pygmy chimpanzee Savage-Rumbaugh (1990) taught Kanzi to communicate with humans by pressing buttons that contained symbols for words. Although the structure of his vocal apparatus prevented Kanzi from talking with his human companions, he often tried to do so. This slide shows examples of some sentences with which Kanzi was tested and the actions that he took. Source: Savage-Rumbaugh, E.S., Language acquisition in nonhuman species, Development Psychobiology, 1990, 23, 599–620. Copyright © 1990, this material is used by permission of John Wiley & Sons, Inc.

Words into thoughts and thoughts into words To produce meaningful communication, we need to convert perceptions, memories and thoughts into speech. Neural mechanisms that control speech production are located in the frontal lobes; those controlling speech comprehension are in the posterior (temporal and parietal) brain regions. Broca’s area is associated with speech production; damage to this region disrupts the ability to speak (production (Broca’s) aphasia). Comprehension of speech begins in the auditory system which analyses sequences of sounds and recognises them as words. Wernicke’s area is associated with language comprehension; damage to this region results in poor speech comprehension and production of meaningless speech (sensory (Wernicke’s) aphasia). Damage to the posterior language areas produces isolation aphasia.

Types of aphasia The most common types of aphasia are summarised in this slide - their primary symptoms and the sites of the associated brain lesions.

Types of dyslexia Types of dyslexia are summarised in this slide - their primary symptoms and the brain regions associated with them.

A hypothetical explanation of phonological dyslexia Phonological dyslexia provides evidence that whole-word reading and phonological reading involve different brain mechanisms. Patients with phonological dyslexia display a selective impairment in the ability to read pseudowords and pronounceable non-words but the ability to read real words is retained. Phonetic reading, which is the only way that we can read non-words or unfamiliar real words, entails letter-to-sound decoding. It also requires more than decoding of sounds produced by single letters: some sounds are transcribed as two-letter sequences (e.g. ‘th’ and ‘sh’) and adding an ‘e’ to the end of a word lengthens an internal vowel (e.g. ‘can’ becomes ‘cane’). Therefore, phonological dyslexia is an impairment in the grapheme-phoneme processing route of the dual-route model of reading.

PET scans of reading Petersen et al (1988, 1990) conducted the first PET investigations of language processing in healthy individuals. This slide shows the medial surface of the brains of people from one of these studies during the reading of letter-like forms (A), strings of consonants (B), pronounceable non-words (C), and real words (D). Source: Petersen, S.E., Fox, P.T., Snyder, A.Z. and Raichle, M.E., Activation of extrastriate and frontal cortical areas by visual words and word-like stimuli. Science, 1990, 249, 1041–1044. © 1990 American Association for the Advancement of Science, reprinted by permission of the authors and publishers.

Reading in Italian and English The different reading strategies used by English and Italian speakers are reflected in different types of brain activation. Italian speakers show greater activation in areas responsible for processing phonemes (left temporal regions) whereas English speakers show greater activation in other areas of the temporal cortex and frontal cortex (areas activated during word retrieval and naming). Source: Fiez, J., Sound and meaning: How native language affects reading strategies. Nature Neuroscience, 2000, 3(1), 3–5, reprinted by permission of the author and Nature Publishing Group.