The syntactic complexity of a regular language is the cardinality of its syntactic semigroup. The syntactic complexity of a subclass of the class of regular languages is the maximal syntactic complexity of languages in that class, taken as a function of the state complexity n of these languages. We study the syntactic complexity of suffix-, bifix-, and factor-free regular languages, star-free languages including three subclasses, and R- and J-trivial regular languages. We found upper bounds on the syntactic complexities of these classes of languages. For R- and J-trivial regular languages, the upper bounds are n! and ⌊e(n-1)!⌋, respectively, and they are tight for n >= 1. Let C^n_k be the binomial coefficient ``n choose k''. For monotonic languages, the tight upper bound is C^{2n-1}_n. We also found tight upper bounds for partially monotonic and nearly monotonic languages. For the other classes of languages, we found tight upper bounds for languages with small state complexities, and we exhibited languages with maximal known syntactic complexities. We conjecture these lower bounds to be tight upper bounds for these languages. We also observed that, for some subclasses C of regular languages, the upper bound on state complexity of the reversal operation on languages in C can be met by languages in C with maximal syntactic complexity. For R- and J-trivial regular languages, we also determined tight upper bounds on the state complexity of the reversal operation.

This study investigated the lifespan influences of task type and working memory on the syntactic complexity of narrative discourse production. Participants included 180 healthy adults across three age cohorts: 20-29 years (Young Group), 60-69 years (Older Group) and 75-89 years (Elderly Group). Participants completed standardized working memory measures and four discourse tasks (single/sequential picture description, storytelling and personal recount). Syntactic complexity for each sample was measured via clausal density yielding a complexity index. For analysis, participants were placed into one of two groups based on working memory scores above (High Working Memory Group) or below (Low Working Memory Group) the mean. Significant differences in syntactic complexity between working memory groups were found for the single picture description and the storytelling; individuals in the high working memory group produced language with greater syntactic complexity. When the effects of cohort and working memory were investigated with a two-way ANOVA, working memory group was no longer significantly related to syntactic complexity. However, there was a significant relationship between cohort and syntactic complexity for the single picture description and storytelling tasks. Analyses indicate that the relationships between syntactic complexity, age, and working memory are dependent on task type.

The syntactic complexity of a regular language is the cardinality of its syntactic semigroup. The syntactic complexity of a subclass of the class of regular languages is the maximal syntactic complexity of languages in that class, taken as a function of the state complexity n of these languages. We study the syntactic complexity of suffix-, bifix-, and factor-free regular languages, star-free languages including three subclasses, and R- and J-trivial regular languages. We found upper bounds on the syntactic complexities of these classes of languages. For R- and J-trivial regular languages, the upper bounds are n! and ⌊e(n-1)!⌋, respectively, and they are tight for n >= 1. Let C^n_k be the binomial coefficient ``n choose k''. For monotonic languages, the tight upper bound is C^{2n-1}_n. We also found tight upper bounds for partially monotonic and nearly monotonic languages. For the other classes of languages, we found tight upper bounds for languages with small state complexities, and we exhibited languages with maximal known syntactic complexities. We conjecture these lower bounds to be tight upper bounds for these languages. We also observed that, for some subclasses C of regular languages, the upper bound on state complexity of the reversal operation on languages in C can be met by languages in C with maximal syntactic complexity. For R- and J-trivial regular languages, we also determined tight upper bounds on the state complexity of the reversal operation.

Esta dissertação utiliza simulações computacionais visando investigar a influência de alguns fatores lingüísticos na organização lexical de verbos, analisando os processos de aquisição e uso. Os fatores testados são: freqüência de observação na linguagem, polissemia e complexidade sintática. Os dados utilizados foram obtidos por meio de tarefas psicolingüísticas de nomeação de ações, realizadas por crianças e adultos (falantes do Português brasileiro), posteriormente representados como grafos. Com base nos fatores lingüísticos, foram formuladas hipóteses relativas ao desenvolvimento da língua, testadas por meio de simulações computacionais denominadas ‘involuções’. Os testes incluem métricas da teoria dos grafos e medidas de similaridade de conjuntos (coeficiente de Jaccard e suas componentes). Os resultados obtidos apontam para uma confirmação das hipóteses formuladas. Adicionalmente, permitiram verificar algumas características do desenvolvimento lingüístico, como o aumento do vocabulário e uma progressiva especialização. / This dissertation uses computational simulations designed to investigate the influence of three linguistic factors in the lexical organization of verbs, analyzing the process of acquisition and use. The tested factors are: frequency of observation in the language, polysemy and syntactic complexity. The data used were obtained from psycholinguistic action naming tasks performed by children and adults (speakers of Brazilian Portuguese), and subsequently represented as graphs. Based on linguistic factors, hypotheses were formulated concerning the development of language, tested through simulations called ‘involutions’. Tests include graph theory metrics and set similarity measures (Jaccard’s coefficient and its components). Results suggest a confirmation of the given hypotheses. Additionally, allowed verification of some language development features, such as vocabulary growth and a progressive specialization.

Esta dissertação utiliza simulações computacionais visando investigar a influência de alguns fatores lingüísticos na organização lexical de verbos, analisando os processos de aquisição e uso. Os fatores testados são: freqüência de observação na linguagem, polissemia e complexidade sintática. Os dados utilizados foram obtidos por meio de tarefas psicolingüísticas de nomeação de ações, realizadas por crianças e adultos (falantes do Português brasileiro), posteriormente representados como grafos. Com base nos fatores lingüísticos, foram formuladas hipóteses relativas ao desenvolvimento da língua, testadas por meio de simulações computacionais denominadas ‘involuções’. Os testes incluem métricas da teoria dos grafos e medidas de similaridade de conjuntos (coeficiente de Jaccard e suas componentes). Os resultados obtidos apontam para uma confirmação das hipóteses formuladas. Adicionalmente, permitiram verificar algumas características do desenvolvimento lingüístico, como o aumento do vocabulário e uma progressiva especialização. / This dissertation uses computational simulations designed to investigate the influence of three linguistic factors in the lexical organization of verbs, analyzing the process of acquisition and use. The tested factors are: frequency of observation in the language, polysemy and syntactic complexity. The data used were obtained from psycholinguistic action naming tasks performed by children and adults (speakers of Brazilian Portuguese), and subsequently represented as graphs. Based on linguistic factors, hypotheses were formulated concerning the development of language, tested through simulations called ‘involutions’. Tests include graph theory metrics and set similarity measures (Jaccard’s coefficient and its components). Results suggest a confirmation of the given hypotheses. Additionally, allowed verification of some language development features, such as vocabulary growth and a progressive specialization.

Esta dissertação utiliza simulações computacionais visando investigar a influência de alguns fatores lingüísticos na organização lexical de verbos, analisando os processos de aquisição e uso. Os fatores testados são: freqüência de observação na linguagem, polissemia e complexidade sintática. Os dados utilizados foram obtidos por meio de tarefas psicolingüísticas de nomeação de ações, realizadas por crianças e adultos (falantes do Português brasileiro), posteriormente representados como grafos. Com base nos fatores lingüísticos, foram formuladas hipóteses relativas ao desenvolvimento da língua, testadas por meio de simulações computacionais denominadas ‘involuções’. Os testes incluem métricas da teoria dos grafos e medidas de similaridade de conjuntos (coeficiente de Jaccard e suas componentes). Os resultados obtidos apontam para uma confirmação das hipóteses formuladas. Adicionalmente, permitiram verificar algumas características do desenvolvimento lingüístico, como o aumento do vocabulário e uma progressiva especialização. / This dissertation uses computational simulations designed to investigate the influence of three linguistic factors in the lexical organization of verbs, analyzing the process of acquisition and use. The tested factors are: frequency of observation in the language, polysemy and syntactic complexity. The data used were obtained from psycholinguistic action naming tasks performed by children and adults (speakers of Brazilian Portuguese), and subsequently represented as graphs. Based on linguistic factors, hypotheses were formulated concerning the development of language, tested through simulations called ‘involutions’. Tests include graph theory metrics and set similarity measures (Jaccard’s coefficient and its components). Results suggest a confirmation of the given hypotheses. Additionally, allowed verification of some language development features, such as vocabulary growth and a progressive specialization.

This study compared seven syntactic measures which can be automatically generated by the Computerized Profiling (CP) software: Mean Length of Utterance in morphemes or words (MLUm or MLUw), Mean Syntactic Length (MSL), the Index of Productive Syntax (IPSyn), the Picture Elicited Scoring Procedure (PESP) for the Language Analysis Remediation and Screening Profile (LARSP), the Syntactic Complexity Score (MSC) scoring of LARSP, and Developmental Sentence Scoring (DSS). Language samples came from 192 children, 106 typically developing children, ages 5;6 to 11;2 and 86 children with language impairment, ages 5;6 to 11;1. Patterns of correlation were consistent for children with or without language impairment. All measures were computed with CP software, and all coding decisions that were made by the software were accepted. The three measures of length (MLUm, MLUw, and MSL) were highly intercorrelated. MSC correlated with the measures of length and with DSS. DSS correlated with the length measures, though not as highly as MSC. DSS also correlated with IPSyn. IPSyn correlated moderately with PESP, correlated less with MSC, and correlated the least with the measures of length. PESP correlated moderately with each measure. PESP, DSS, and IPSyn correlated more highly for the children with language impairment. These measures correlated highly sometimes and sometimes they did not correlate much. This suggests that they are measuring different aspects of syntactic ability.

Research has shown that children with Language Impairment (LI) struggle with social communication skills in addition to their characteristic syntactic difficulties. This pilot study analyzed the potential change in grammatical complexity in narratives of five children with LI when enrolled in a social communication intervention. The intervention itself focused on teaching emotion understanding by reading and reenacting children’s stories and journaling. Grammatical limitations were indirectly addressed by clinician modeling of complex forms during the intervention sessions. Each child’s productions were assessed and analyzed for grammatical complexity during retelling a book in the Mercer Mayer “a boy, a dog, and a frog” series. The children performed this task once a week during the course of the intervention. Specific measures used included the average length of terminable unit (T-unit) and the number of subordinate clauses used in each narrative. Three students’ productions remained steady throughout the course of the interventions; their grammatical complexity neither increased nor decreased. One student’s production showed a clear decrease in complexity but was explained by an obvious and arguably more creative change in her language output. One student’s grammatical complexity increased throughout the sessions as indicated by a steady increase in the average length of T-unit. Thus, the results of this study were equivocal. There were several limitations, however, that might be addressed in future intervention studies.

The present study investigates the effect of genre on lexical and syntactic complexity. The corpus used for this study is made up of argumentative and narrative texts from the TRAWL (Tracking Written Learner Language) online corpus. The study analyses texts written by 22 Norwegian EFL learners, 10 in year 8 and 12 in year 9. One narrative text and one argumentative text from each student is analysed using an automated method to calculate complexity based on one measure of lexical complexity, the Guiraud Index and two measures of syntactic complexity, mean length of sentence and mean length of t-unit. A qualitative analysis, comparing outlying results to the Swedish National curriculum, also gave insight into different levels of complexity. Previous studies suggest that narrative texts have more lexical complexity while argumentative texts are more syntactically complex. The results of this study support this hypothesis though not all correlations were found to be statistically significant.

Developing syntactic complexity in writing is an important goal for many adult language learners. However, little is known about the effect of different writing practice tasks on the development of syntactic complexity. Furthermore, it is unclear to what degree syntactic complexity is related to writing quality. The main purpose of this study was to compare the longitudinal effects of three types of writing tasks on the development of syntactic complexity and writing quality. In order to investigate these relationships, a mixed-methods design was used. A quantitative component that was a quasi-experimental, longitudinal investigation was combined with an embedded qualitative component which involved eliciting stimulated recalls from participants from two of the experimental groups in the study. For the quantitative component, the participants (N = 105) were first-year, non-English majors at a four-year, co-educational university in western Japan. The participants were randomly divided into two groups: a sentence-combining group and a translation group. These two experimental groups were compared to an intact timed-writing group, which served as a comparison group. Writing samples were collected at three points throughout the year and analyzed based on five measures of syntactic complexity: mean length of sentence, mean length of T-unit, mean length of clause, clauses per T-unit, and T-units per sentence. Repeated-measures ANOVAs were used to analyze the five measures to investigate statistical differences across time for each group. One-way ANOVAs were used to analyze the five measures to ascertain differences between groups at each time. Furthermore, all the writing samples were evaluated by human raters for writing quality using an analytic rubric. Ratings were analyzed and investigated for changes in quality across time and between groups, as well as to examine the overall relationship between syntactic complexity and quality. For the qualitative component, seven participants were selected from the experimental groups to participate in stimulated recalls. The data were analyzed and coded to investigate the cognitive processes underlying each task. The results of the quantitative study indicated that the participants in the translation and sentence-combining groups made small, but significant gains in syntactic complexity across time. The translation group made significant growth on clauses per T-unit while the sentence-combining group made significant growth across time on mean length of sentence, mean length of T-unit, and T-units per sentence. The timed-writing group was not able to sustain significant growth across time. In the between-groups analyses, there were significant differences between the sentence-combining group and the other groups on mean length of sentence and T-units per sentence, indicating that the participants in that group demonstrated more coordination, and to a lesser degree, more subordination in their writing. In terms of quality of writing, the results indicated an overall weak, statistically significant positive correlation between measures of syntactic complexity and human rating judgments. Among all of the syntactic measures, T-units per sentence correlated the strongest with rating scores. The results of the qualitative component indicated that the participants practicing sentence-combining tasks focused most of their attention toward syntactic aspects of language while the participants in the translation group focused their attention on lexical aspects of language while performing the tasks. The findings of this study show that the development of syntactic complexity is influenced by writing practice tasks and that tasks that direct learners’ attention toward features of the language are more likely to hasten the development of syntactic complexity. Among the tasks, sentence-combining showed the most potential in developing syntactic complexity, particularly for increasing the use of compound sentences. However, none of the writing practice tasks led to significant gains in writing quality, in part because syntactic complexity was shown to have a moderately weak relationship to overall writing quality. / Teaching & Learning