Measures Of Lexical Diversity Research Articles

Lexical Diversity and Omission Errors as Predictors of Language Ability in the Narratives of Sequential Spanish–English Bilinguals: A Cross-Language Comparison

This study explored the utility of language sample analysis for evaluating language ability in school-age Spanish-English sequential bilingual children. Specifically, the relative potential of lexical diversity and word/morpheme omission as predictors of typical or atypical language status was evaluated. Narrative samples were obtained from 48 bilingual children in both of their languages using the suggested narrative retell protocol and coding conventions as per Systematic Analysis of Language Transcripts (SALT; Miller & Iglesias, 2008) software. An additional lexical diversity measure, VocD, was also calculated. A series of logistical hierarchical regressions explored the utility of the number of different words, VocD statistic, and word and morpheme omissions in each language for predicting language status. Omission errors turned out to be the best predictors of bilingual language impairment at all ages, and this held true across languages. Although lexical diversity measures did not predict typical or atypical language status, the measures were significantly related to oral language proficiency in English and Spanish. The results underscore the significance of omission errors in bilingual language impairment while simultaneously revealing the limitations of lexical diversity measures as indicators of impairment. The relationship between lexical diversity and oral language proficiency highlights the importance of considering relative language proficiency in bilingual assessment.

Relationships between text length and lexical diversity measures: Can we use short texts of less than 100 tokens?

Lexical diversity (LD) measures have been known to be sensitive to the length of the text, and numerous revised LD measures have been proposed. This study aims to identify LD measures that are least affected by text length and can be used for the analysis of short L2 texts (50-200 tokens). This study compares the type-token ratio, Guiraud index, D, and measure of textual lexical diversity (MTLD) to assess their degree of susceptibility to text length. Spoken texts of 200 tokens from 20 L2 English learners at the lower-intermediate-level were divided into segments of 50 to 200 tokens and the text length impact was examined. It was found that MTLD was least affected by text length, and that it should be used with texts of at least 100 tokens.

Withdrawal notice to: Effects of text length on lexical diversity measures: Using short texts with less than 200 tokens

The publisher regrets sincerely that an error in its production office resulted in the below article appearing in this issue twice. To remedy this error, pages 522–532 from this issue have been retracted. SYS, 40 (2012) 522–532, http://dx.doi.org/10.1016/j.system.2012.10.017 . The duplicate article has therefore been withdrawn. As a consequence, pages 522–532 related to the duplicate article are missing from the printed issue. The publisher sincerely apologizes for any inconvenience this may cause.

WITHDRAWN: Effects of text length on lexical diversity measures: Using short texts with less than 200 tokens

The publisher regrets sincerely that an error in its production office resulted in the below article appearing in this issue twice. To remedy this error, pages 522-532 from this issue have been retracted. < SYS , 40 (2012) 522–532>, http://dx.doi.org/10.1016/j.system.2012.10.017 . The duplicate article has therefore been withdrawn. As a consequence, pages 522-532 related to the duplicate article are missing from the printed issue. The publisher apologizes for any inconvenience this may cause.

Effects of text length on lexical diversity measures: Using short texts with less than 200 tokens

Despite the importance of lexical diversity (LD) in L2 speaking and writing performance, LD assessment measures are known to be affected by the number of words analyzed in the text. This study aims to identify LD measures that are least affected by text length and can be used for the analysis of short L2 texts (50–200 tokens). We compared the type–token ratio, Guiraud index, Maas, measure of textual lexical diversity (MTLD), D, and HD–D to assess their robustness in relation to text length variation. Spoken texts of 200 tokens from 38 L2 English learners at the lower–intermediate-level were divided into segments of 50–200 tokens and the text length impact was examined. We found that MTLD was least affected by text length across most ranges, but was somewhat affected across 50–150 and 50–200 tokens. We further observed low correlations between equal-sized texts for up to 100 tokens. These results suggest that MTLD can be used with texts of more than 100 tokens and MTLD values can be compared between texts across 100 and 200 tokens. We also showed that D and HD–D produced similar results for texts; this indicates that D and HD–D are comparable.

Narrative Ability of Children With Speech Sound Disorders and the Prediction of Later Literacy Skills

The main purpose of this study was to examine how children with isolated speech sound disorders (SSDs; n = 20), children with combined SSDs and language impairment (LI; n = 20), and typically developing children (n = 20), ages 3;3 (years;months) to 6;6, differ in narrative ability. The second purpose was to determine if early narrative ability predicts school-age (8-12 years) literacy skills. This study employed a longitudinal cohort design. The children completed a narrative retelling task before their formal literacy instruction began. The narratives were analyzed and compared for group differences. Performance on these early narratives was then used to predict the children's reading decoding, reading comprehension, and written language ability at school age. Significant group differences were found in children's (a) ability to answer questions about the story, (b) use of story grammars, and (c) number of correct and irrelevant utterances. Regression analysis demonstrated that measures of story structure and accuracy were the best predictors of the decoding of real words, reading comprehension, and written language. Measures of syntax and lexical diversity were the best predictors of the decoding of nonsense words. Combined SSDs and LI, and not isolated SSDs, impact a child's narrative abilities. Narrative retelling is a useful task for predicting which children may be at risk for later literacy problems.

Productive vocabulary across discourse types

Aims: The goals of the study were (a) to examine the effect of discourse type on lexical diversity by testing whether there are significant differences among language samples elicited using four discourse tasks (procedures, eventcasts, story telling, and recounts); and (b) to assess the extent to which age influences lexical diversity when different types of discourse are elicited. Methods & Procedures: A total of 86 cognitively healthy adults participated in the study and comprised two groups – young adults (20–29 years old) and older adults (70–89 years old). Participants completed the discourse tasks and their language samples were analysed using dedicated software (voc-D) to obtain estimates of their lexical diversity. Outcomes & Results: A mixed 2 × 4 ANOVA was conducted and followed by an investigation of simple main effects. A lexical diversity hierarchy was established that was similar for both age groups. The study also uncovered age-related differences that were evident when the stimuli were verbally presented but were eliminated when the language samples were elicited using pictorial stimuli. Conclusions: Results indicated that lexical diversity is one of the microlinguistic indices that are influenced by discourse type and age, a finding that carries important methodological implications. Future investigations are warranted to explore the patterns of lexical diversity in individuals with neurogenic language disorders and assess the clinical utility of measures of lexical diversity.

Volubility as a mediator in the associations between conversational language measures and child temperament

Despite support for the use of conversational language measures, concerns remain regarding the extent to which they may be confounded with aspects of child temperament, extraversion in particular. This study of 161 twins from the Western Reserve Reading Project (WRRP) examined the associations between children's conversational language use and three key aspects of child temperament: Surgency (i.e., introversion/extraversion), Effortful Control (i.e., attention and task persistence) and Negative Affectivity (e.g., fear, anger, sadness). Child biological sex was considered as a possible moderating factor. Correlational analyses were conducted between aspects of temperament during early school-age years (i.e., 7-8 years), as measured by the Children's Behavior Questionnaire-Short Form (CBQ), and six different measures of children's conversational language use: total number of complete and intelligible utterances (TCICU), number of total words (NTW), mean length of utterance (MLU), total number of conjunctions (TNC), number of different words (NDW) and measure D (i.e., a measure of lexical diversity). Values for NTW, TNC and NDW were derived both on the entire sample and on the first 100 C-units. Correlations between language and temperament were compared between girls and boys using the Fisher r-to-z transformation to examine the significance of potential moderating effects. Children's reported variability in Effortful Control did not correlate significantly with any of the child language measures. In contrast, children's Negative Affectivity and Surgency tended to demonstrate positive, albeit modest, correlations with those conversational language measures that were derived from the sample as a whole, rather than from a standardized number of utterances. MLU, as well as measures of NDW and NTW derived from standardized sample lengths of 100 C-units, did not correlate with any measure of child temperament. TNC demonstrated an unexpected negative correlation with child Surgency when it was derived from a standardized number of C-units, but not when derived from the entire sample length. Child biological sex did not moderate the significant associations between language and temperament measures. Overall, measures that control for volubility did not correlate significantly with child temperament; however, measures that reflected volubility tended to correlate weakly with some aspects of temperament, particularly Surgency. Results provide a degree of discriminant evidence for the validity of MLU and measures of type (i.e., NDW) and token use (i.e., NTW) when derived from a standardized number of utterances.

Homelands of the world’s language families

A systematic, computer-automated tool for narrowing down the homelands of linguistic families is presented and applied to 82 of the world’s larger families. The approach is inspired by the well-known idea that the geographical area of maximal diversity within a language family corresponds to the original homeland. This is implemented in an algorithm which takes a lexicostatistically derived distance measure and a geographical distance measure and computes a lexical diversity measure for each language in the family relative to all the other related languages. The location of the language with the highest diversity measure is heuristically identified with the homeland.

Language Sampling: Does the Length of the Transcript Matter?

Language sample analysis is considered by many to be the gold standard for documenting children's oral language skills. One limitation, however, is the time required for collection and transcription of language samples. The goal of this study was to determine if stable language sample measures could be generated using relatively short language samples. Measures were generated from children's conversational and narrative language samples after they were broken into three lengths (1-, 3-, and 7-min samples). The measures were compared to determine the stability of measures from the short samples (1 and 3 min) when compared to measures from the long sample (7 min). The measures were further analyzed to determine if differences across transcript cuts varied as a function of age group (2;8 [years;months]-5;11 vs. 6;0-13;3) or sampling context (conversation vs. narrative). Overall, the language sample measures were quite consistent across the transcript cuts. Measures of productivity, lexical diversity, and utterance length were the most reliable when short samples were used. Implications for the efficient use of language sample analysis in clinical protocols are discussed. A framework for eliciting reliable short samples is provided.

MTLD, vocd-D, and HD-D: A validation study of sophisticated approaches to lexical diversity assessment

The main purpose of this study was to examine the validity of the approach to lexical diversity assessment known as the measure of textual lexical diversity (MTLD). The index for this approach is calculated as the mean length of word strings that maintain a criterion level of lexical variation. To validate the MTLD approach, we compared it against the performances of the primary competing indices in the field, which include vocd-D, TTR, Maas, Yule's K, and an HD-D index derived directly from the hypergeometric distribution function. The comparisons involved assessments of convergent validity, divergent validity, internal validity, and incremental validity. The results of our assessments of these indices across two separate corpora suggest three major findings. First, MTLD performs well with respect to all four types of validity and is, in fact, the only index not found to vary as a function of text length. Second, HD-D is a viable alternative to the vocd-D standard. And third, three of the indices--MTLD, vocd-D (or HD-D), and Maas--appear to capture unique lexical information. We conclude by advising researchers to consider using MTLD, vocd-D (or HD-D), and Maas in their studies, rather than any single index, noting that lexical diversity can be assessed in many ways and each approach may be informative as to the construct under investigation.

Cutting the Gordian Knot: The Moving-Average Type–Token Ratio (MATTR)

Type–token ratio (TTR), or vocabulary size divided by text length (V/N), is a time-honoured but unsatisfactory measure of lexical diversity. The problem is that the TTR of a text sample is affected by its length. We present an algorithm for rapidly computing TTR through a moving window that is independent of text length, and we demonstrate that this measurement can detect changes within a text as well as differences between texts.

Validity of a Parent Report Instrument for Irish-speaking Toddlers

Previous research has demonstrated the validity of parent report as an assessment of early vocabulary and grammatical development across a range of languages.This study adapted a well-known tool, the MacArthur—Bates Communicative Development Inventories (MCDI), to Irish (ICDI), in order to measure vocabulary and grammatical development longitudinally across a sample of 21 children. Results from the parent checklists were validated against spontaneous language samples. Correlations demonstrated high concurrent validity for ICDI reported vocabulary with measures of lexical diversity derived from the spontaneous samples. In addition, ICDI measures of grammar also correlated highly with various indices of grammar from the spontaneous samples. Although both ICDI and spontaneous vocabulary measures were highly correlated, the ICDI checklist includes a broader range of language skills and so would seem to capture the range of language ability more comprehensively than direct observation. The findings have implications for developing parent report measures of early language development in highly inflected languages.

Individual differences and language interdependence: a study of sequential bilingual development in Spanish–English preschool children

The purpose of the current study is to examine language influence in sequential bilinguals. Specifically, this study evaluates whether performance in a first language predicts success in the acquisition of a second language nine months after exposure to the second language begins. Forty-nine Spanish-speaking children attending English-only pre-kindergarten classrooms participated in the study. Children were assessed in Spanish at the beginning of the school year using the Spanish version of the Bilingual English Spanish Assessment (BESA), MLU in words, and a lexical diversity measure, D, obtained from a language sample. Nine months later, children were assessed in English using the English-BESA. Analyses indicated significant correlations between semantic and grammatical measures across languages. Stepwise regression analyses found that grammatical and semantic measures in the first language robustly predicted grammatical and semantic measures in the second language. We propose that native language skills predict the success in second language acquisition, not because of linguistic transfer, but by virtue of individual differences in language learning abilities present in typical populations.

Lexical Diversity in Writing and Speaking Task Performances

In the rating scales of major international language tests, as well as in automated evaluation systems (e.g. e-rater), a positive relationship is often claimed between lexical diversity, holistic quality of written or spoken discourses, and language proficiency of candidates. This article reports a posteriori validation study that analysed a sample of the archived data of an international language test to examine empirically to what extent such relationships exist. It is also noted that previous studies on lexical diversity in the field of applied linguistics have focused exclusively on either written or spoken discourses, no study to date has compared lexical diversity of spoken and written discourses produced by the same participants. Therefore, the second aim of this article is to understand the differences in lexical diversity between writing and speaking task performances, and to what extent the topics of the writing prompts may affect lexical diversity of written discourses. Using D as a measure of lexical diversity (Malvern and Richards 1997, 2002; Malvern et al.2004), it was found that D had a statistically significant and positive correlation with the overall quality ratings of both writing and speaking performances as well as the candidates’ general language proficiency. Nevertheless, the significant relationships were not borne out across the subgroups of the sample in terms of gender, first language background, purpose of taking the test and topics of the writing prompts. The different writing topics also had significant effects on lexical diversity—especially the topics that candidates were highly familiar with—even after controlling for writing ability and overall language proficiency. The lexical diversity of candidates’ writing and speaking performances were approximately at the same level; further, D was found to be a better predictor of speaking than writing performance. The implications of these findings are discussed with specific reference to the use of lexical diversity measures to inform language test validation and the development of lexical diversity parameters in automated evaluation systems.

Measuring L2 Lexical Growth Using Hypernymic Relationships

This study investigated second language (L2) lexical development in the spontaneous speech of six adult, L2 English learners in a 1‐year longitudinal study. One important aspect of lexical development is lexical organization and depth of knowledge. Hypernymic relations, the hierarchical relationships among related words that vary in relation to their semantic specificity (e.g., Golden Retriever vs. dog vs. animal), are an important indicator of both lexical organization and depth of knowledge. Thus, this study used hypernymy values from the WordNet database and a lexical diversity measure to analyze lexical development. Statistical analyses in this study indicated that both hypernymic relations and lexical diversity in L2 learners increase over time. Additionally, lexical diversity and hypernymic values correlated significantly, suggesting that as learners' lexicons grow, learners have access to a wider range of hypernymy levels. These findings are discussed in relation to developing abstractness in language, extending hypernymic knowledge, and the growth of lexical networks.

A cross-linguistic and bilingual evaluation of the interdependence between lexical and grammatical domains

The purpose of this study was to examine within and across language relationships between lexical and grammatical domains by focusing on measures of lexical diversity and grammatical complexity in Spanish and English. One hundred and ninety-six preschool and school-aged Latino children with different levels of English and Spanish proficiencies and different language abilities produced narratives in Spanish, English, or both. Analyses revealed strong associations between lexical (number of different words and number of different verbs) and grammatical measures (mean length of utterances in words and use of ditransitive predicates), supporting the domain interdependence hypothesis within a language. Cross-linguistic comparisons indicate a greater diversity of verbs and ditransitive predicates in Spanish compared to English for this population. In the language samples of children who produced narratives in the two languages, there was no relationship between the two domains across languages. The lack of cross-language correlations may be related to other variables influencing lexical and semantic development in bilingual learners. Methodological issues to be considered in future studies with bilingual speakers are discussed.

Theory of mind and use of cognitive state terms by adolescents with traumatic brain injury

Background: There is growing evidence of impaired social cognition in individuals with traumatic brain injury (TBI). Social cognition tests, however, place demands on domain‐general cognitive functions such as auditory working memory, so that test scores might reflect the influence of these factors on test performance rather than domain‐specific social cognition impairments. As an alternative, we examined conversations of adolescents with TBI for evidence of cognitive state terms. This work was completed in partial fulfilment of the requirements for a Master of Science Degree at the University of Wisconsin. The first author wishes to thank the members of her thesis committee, Dr Jon Miller, Dr Nadine Connor, and Dr Julia Evans; and also the SALT transcription laboratory members. This work was supported in part by Grant DC00163 from the National Institute on Deafness and Other Communication Disorders and funding from the Wisconsin Alumni Research Fund, to Dr Turkstra. Methods and Procedures: Participants were 16 adolescents with TBI, who were divided into two groups (TBI‐Low and TBI‐High) based on scores on a test of theory of mind (ToM), and 8 typically developing (TD) adolescents matched to participants in the TBI groups for age and race. Each participant completed a 3‐minute conversation with a peer or researcher partner, and conversations were analysed to determine the number of cognitive state terms relative to total words produced. Outcomes and Results: The TBI‐Low group expressed significantly fewer cognitive state terms and significantly fewer self‐ vs other‐referenced terms than either the TBI‐High or TD group. There was no significant difference between the TD and TBI‐High groups. The findings were not related to generally impoverished language in the TBI‐Low group, as the three groups were similar on measures of lexical diversity. Conclusions: The findings support the hypothesis that adolescents with TBI have domain‐specific deficits in social cognition, beyond what might be accounted for by the cognitive demands of social cognition tests. Given the relation of social cognitive ability to important life outcomes, these skills should be included in the evaluation of individuals with cognitive‐communication disorders after TBI.

A Preliminary Examination of Vocabulary and Word Learning in African American Toddlers From Middle and Low Socioeconomic Status Homes

This study examined the effect of socioeconomic status (SES) on the early lexical performance of African American children. Thirty African American toddlers (30 to 40 months old) from low-SES (n = 15) and middle-SES (n = 15) backgrounds participated in the study. Their lexical-semantic performance was examined on 2 norm-referenced standardized tests of vocabulary, a measure of lexical diversity (number of different words) derived from language samples, and a fast mapping task that examined novel word learning. Toddlers from low-SES homes performed significantly poorer than those from middle-SES homes on standardized receptive and expressive vocabulary tests and on the number of different words used in spontaneous speech. No significant SES group differences were observed in their ability to learn novel word meanings on a fast mapping task. The influence of socioeconomic background on African American children's lexical semantic tasks varies with the type of measure used.

Do children with Williams syndrome have unusual vocabularies?

Aims The present study investigated whether children with Williams syndrome (WS) produced a higher number of different word roots and low-frequency words in spontaneous speech in a topic controlled setting. Method A group of children with WS was compared to a group of typically developing children matched for chronological age (CA), and a group of typically developing children matched for receptive language abilities (LA). A further comparison was made between the WS group and a group of children matched for non-verbal abilities (NA). Spontaneous speech was elicited using a narrative task. The data were analysed using three different measures of lexical diversity. The results revealed that the children with WS neither produce a higher number of different word roots nor significantly more low-frequency items in comparison to the CA, LA and NA matched participants. Furthermore, language and non-verbal abilities did not predict the number of different and low frequency words used by the typically developing children, however in the WS group non-verbal abilities predicted the number of low-frequency words and receptive language skills predicted the number of different words produced. It is concluded that individuals with WS do not have unusual vocabularies and that the subdomain of language, lexical semantics, does not seem to be an independent cognitive skill.