What Language Disorders Reveal About the Mechanisms of Morphological Processing

We addressed an understudied topic in the literature of language disorders, that is, processing of derivational morphology, a domain which requires integration of semantic and syntactic knowledge. Current psycholinguistic literature suggests that word processing involves morpheme recognition, which occurs immediately upon encountering a complex word. Subsequent processes take place in order to interpret the combination of stem and affix. We investigated the abilities of individuals with agrammatic (PPA-G) and logopenic (PPA-L) variants of primary progressive aphasia (PPA) and individuals with stroke-induced agrammatic aphasia (StrAg) to process pseudowords which violate either the syntactic (word class) rules (*reheavy) or the semantic compatibility (argument structure specifications of the base form) rules (*reswim). To this end, we quantified aspects of word knowledge and explored how the distinct deficits of the populations under investigation affect their performance. Thirty brain-damaged individuals and 10 healthy controls participated in a lexical decision task. We hypothesized that the two agrammatic groups (PPA-G and StrAg) would have difficulties detecting syntactic violations, while no difficulties were expected for PPA-L. Accuracy and Reaction Time (RT) patterns indicated: the PPA-L group made fewer errors but yielded slower RTs compared to the two agrammatic groups which did not differ from one another. Accuracy rates suggest that individuals with PPA-L distinguish *reheavy from *reswim, reflecting access to and differential processing of syntactic vs. semantic violations. In contrast, the two agrammatic groups do not distinguish between *reheavy and *reswim. The lack of difference stems from a particularly impaired performance in detecting syntactic violations, as they were equally unsuccessful at detecting *reheavy and *reswim. Reduced grammatical abilities assessed through language measures are a significant predictor for this performance, suggesting that the “hardware” to process syntactic information is impaired. Therefore, they can only judge violations semantically where both *reheavy and *reswim fail to pass as semantically ill-formed. This finding further suggests that impaired grammatical knowledge can affect word level processing as well. Results are in line with the psycholinguistic literature which postulates the existence of various stages in accessing complex pseudowords, highlighting the contribution of syntactic/grammatical knowledge. Further, it points to the worth of studying impaired language performance for informing normal language processes.

Investigating the Effects of Learning Tasks on Vocabulary Knowledge

<p>This thesis looks at whether different kinds of vocabulary learning tasks result in different types of word knowledge. In almost every study that has investigated the effects of tasks on vocabulary learning; the only aspect of word knowledge that was tested was meaning and form. Since researchers agree that knowing a word involves much more than knowing its meaning and form, prior research may have measured partial knowledge of only one of several aspects of knowledge. In order to determine the effects of vocabulary learning tasks, several aspects of knowledge should be tested. The experiments in this thesis investigated how vocabulary learning tasks affect both receptive and productive knowledge of five aspects of word knowledge: orthography, association, syntax, meaning and form, and grammatical functions. In the first of six experiments, the effects of incidental learning from reading and explicit learning from word pairs on word knowledge were compared. The results indicated that gains in knowledge tend to increase as the number of repetitions increases; however, partial gains from an informative context may be reduced or eliminated if followed by a less informative context. The results also showed that learning from word pairs contributed to surprisingly greater gains in all of the aspects. In the second experiment, two tasks (learning from glossed sentences, and learning from word pairs) were compared to determine the effects of context and synonymy on vocabulary knowledge. It was found that the subjects gained greater knowledge of unknown words that had high frequency synonyms than for those with less frequent synonyms. The results also indicated that a single context may have little effect on acquisition. In the third, fourth and fifth experiments, the effects of receptive and productive learning tasks on vocabulary knowledge were examined. The results indicated that productive learning from word pairs may be more effective at developing productive knowledge while receptive learning from word pairs may be more effective at increasing receptive knowledge. The sixth experiment investigated the effects of receptive and productive learning from word pairs on communication. It was found that the receptive task may be superior in improving comprehension, and the productive task may be better suited to facilitating writing. Taken as a whole, this thesis indicates that measuring multiple aspects of vocabulary knowledge both receptively and productively may provide a much more accurate assessment of the relative efficacy of vocabulary learning tasks. Moreover, it suggests that different tasks may have a different effect on vocabulary knowledge.</p>

Investigating the Effects of Learning Tasks on Vocabulary Knowledge

<p>This thesis looks at whether different kinds of vocabulary learning tasks result in different types of word knowledge. In almost every study that has investigated the effects of tasks on vocabulary learning; the only aspect of word knowledge that was tested was meaning and form. Since researchers agree that knowing a word involves much more than knowing its meaning and form, prior research may have measured partial knowledge of only one of several aspects of knowledge. In order to determine the effects of vocabulary learning tasks, several aspects of knowledge should be tested. The experiments in this thesis investigated how vocabulary learning tasks affect both receptive and productive knowledge of five aspects of word knowledge: orthography, association, syntax, meaning and form, and grammatical functions. In the first of six experiments, the effects of incidental learning from reading and explicit learning from word pairs on word knowledge were compared. The results indicated that gains in knowledge tend to increase as the number of repetitions increases; however, partial gains from an informative context may be reduced or eliminated if followed by a less informative context. The results also showed that learning from word pairs contributed to surprisingly greater gains in all of the aspects. In the second experiment, two tasks (learning from glossed sentences, and learning from word pairs) were compared to determine the effects of context and synonymy on vocabulary knowledge. It was found that the subjects gained greater knowledge of unknown words that had high frequency synonyms than for those with less frequent synonyms. The results also indicated that a single context may have little effect on acquisition. In the third, fourth and fifth experiments, the effects of receptive and productive learning tasks on vocabulary knowledge were examined. The results indicated that productive learning from word pairs may be more effective at developing productive knowledge while receptive learning from word pairs may be more effective at increasing receptive knowledge. The sixth experiment investigated the effects of receptive and productive learning from word pairs on communication. It was found that the receptive task may be superior in improving comprehension, and the productive task may be better suited to facilitating writing. Taken as a whole, this thesis indicates that measuring multiple aspects of vocabulary knowledge both receptively and productively may provide a much more accurate assessment of the relative efficacy of vocabulary learning tasks. Moreover, it suggests that different tasks may have a different effect on vocabulary knowledge.</p>

Effect of Word Exposure Frequency on Chinese Advanced EFL Learners’ Incidental Vocabulary Acquisition

The present study explores the effect of word exposure frequency on Chinese advanced EFL learners’ incidental acquisition of three aspects of word knowledge (i.e., word form, word class and word meaning). The participants were 20 Chinese English postgraduates who read two chapters of an original English novel and took four vocabulary tests. The target words were 20 pseudo-words created to replace the words that naturally occurred from one to twenty times in the text. The results show that word exposure frequency has a significant effect on IVA through reading, exerting the strongest effect on word form recognition and the weakest on word meaning recall. The study also finds that seven is the threshold value for significant word gain growth and that local word frequency also influences learners’ IVA.

Secondary Curriculum Literacy and Teacher Word-Knowledge: Further Findings from a Western Australian ITE Cohort Study

The Australian Government, in its Professional Standards for Teachers and Australian Curriculum framework, requires that all secondary teachers actively teach the specific literacy of their learning area. Yet achievement of that goal hinges on teachers having first acquired the pre-requisite literate competencies during their own schooling. There are reasons to doubt that this is the case for some graduate teachers, which means attempts to raise standards in schools are beset by a troubling circularity. Here we illustrate the problem with further findings from a Western Australian ITE Cohort Study (n=393), focussing this time on the word knowledge of secondary teaching graduates. Our analysis suggests that some secondary ITE students carry shortcomings from their own schooling that may hamper their ability to teach word knowledge or to self-correct. Current training and resources may thus have limited efficacy for some graduating teachers, placing limits on what can be achieved in schools. We consider the implications for literacy policies and for initial teacher education at secondary level.