Scott Jarvis

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.

Methodological Rigor in the Study of Transfer: Identifying L1 Influence in them Interlanguage Lexicon

Numerous conflicting claims exist concerning the nature of L1 influence. This article argues that much of the confusion could be eliminated if a unified framework were established for this area of inquiry. Such a framework would minimally require transfer studies to consider at least 3 potential effects of L1 influence: (a) intra-L1-group similarities, (b) inter-L1-group differences, and (c) L1-IL performance similarities. This study examines all three types ofevidence in the English lexical reference of Finnish-speaking and Swedish-speaking Finns at multiple levels of age and L2 exposure in three different but related elicitation tasks. The results suggest a subtle yet demonstrable presence for L1 influence in this area of interlanguage performance.

Short texts, best-fitting curves and new measures of lexical diversity

Following up on recent work by Malvern and Richards (1997, this issue; McKee et al., 2000) concerning the measurement of lexical diversity through curve fitting, the present study compares the accuracy of five formulae in terms of their ability to model the type-token curves of written texts produced by learners and native speakers. The most accurate models are then used to consider unresolved issues that have been at the forefront of past research on lexical diversity: the relationship between lexical diversity and age, second language (L2) instruction, L2 proficiency, first language (L1) background, writing quality and vocabulary knowledge. The participants in the study comprise 140 Finnish-speaking and 70 Swedish-speakinglearners of English, and an additional group of 66 native English speakers. The data include written narrative descriptions of a silent film, and the results show that two of the curve-fitting formulae provide accurate models of the type-token curves of over 90% of the texts. The texts for which accurate models were obtained were subjected to further analyses, and the results indicate a clear relationship between lexical diversity and amount of instruction, but a more complicated relationship between lexical diversity and L1 background, writing quality and vocabulary knowledge.

vocd: A theoretical and empirical evaluation

A reliable index of lexical diversity (LD) has remained stubbornly elusive for over 60 years. Meanwhile, researchers in fields as varied as stylistics, neuropathology, language acquisition, and even forensics continue to use flawed LD indices — often ignorant that their results are questionable and in some cases potentially dangerous. Recently, an LD measurement instrument known as vocd has become the virtual tool of the LD trade. In this paper, we report both theoretical and empirical evidence that calls into question the rationale for vocd and also indicates that its reliability is not optimal. Although our evidence shows that vocds output (D) is a relatively robust indicator of the aggregate probabilities of word occurrences in a text, we show that these probabilities — and thus also D — are affected by text length. Malvern, Richards, Chipere and Durán (2004) acknowledge that D (as calculated by vocds default method) can be affected by text length, but claim that the effects are not significant for the ranges of text lengths with which they are concerned. In this paper, we explain why D is affected by text length, and demonstrate with an extensive empirical analysis that the effects of text length are significant over certain ranges, which we identify.

Predicting Lexical Proficiency in Language Learner Texts Using Computational Indices.

The authors present a model of lexical proficiency based on lexical indices related to vocabulary size, depth of lexical knowledge, and accessibility to core lexical items. The lexical indices used in this study come from the computational tool Coh-Metrix and include word length scores, lexical diversity values, word frequency counts, hypernymy values, polysemy values, semantic co-referentiality, word meaningfulness, word concreteness, word imagability, and word familiarity. Human raters evaluated a corpus of 240 written texts using a standardized rubric of lexical proficiency. To ensure a variety of text levels, the corpus comprised 60 texts each from beginning, intermediate, and advanced second language (L2) adult English learners. The L2 texts were collected longitudinally from 10 English learners. In addition, 60 texts from native English speakers were collected. The holistic scores from the trained human raters were then correlated to a variety of lexical indices. The researchers found that lexical diversity, word hypernymy values and content word frequency explain 44% of the variance of the human evaluations of lexical proficiency in the examined writing samples. The findings represent an important step in the development of a model of lexical proficiency that incorporates both vocabulary size and depth of lexical knowledge features.

Same Source, Different Outcomes: A Study of Swedish Influence on the Acquisition of English in Finland.

With a Finnish-speaking majority and a Swedish-speaking minority, Finland offers a striking contrast in the kinds of cross-linguistic influence that can occur in the acquisition of English in a multilingual setting. While much previous research has looked at the differences between Finnish and Swedish influences, our study compares Swedish influence on the use of English by native speakers of Swedish and by native speakers of Finnish, both positive and negative transfer being evident in the performances. The findings indicate that although both groups show influence from Swedish, the patterns of transfer are by no means identical.

Conceptual transfer: Crosslinguistic effects in categorization and construal

Research on the relationship between language and cognition in bilinguals has often focused on general effects that are common to bilinguals of all language backgrounds, such as the positive effects of bilingualism in various areas of cognitive development (e.g., Bialystok, 2005; Karmiloff-Smith, 1992). However, there are also language-specific effects in the relationship between language and cognition in bilinguals that emerge in the form of cross-linguistic influence and, in many cases, these cross-linguistic effects do not appear to be confined to purely linguistic (e.g., phonological, morphological, syntactic, semantic) phenomena. For example, bilinguals’ choice of words for referring to objects and actions, as well as their choice of syntactic and discursive structures for referring to events and situations, often reflect ways of conveying meaning and intentions that are specific to particular language backgrounds.

Lexical access and lexical diversity in first language attrition

This paper presents an investigation of lexical first language (L1) attrition, asking how a decrease in lexical accessibility manifests itself in long-term residents in a second language (L2) environment. We question the measures typically used in attrition studies (formal tasks and type–token ratios) and argue for an in-depth analysis of free spoken data, including factors such as lexical frequency and distributional measures. The study is based on controlled, elicited and free data from two populations of attriters of L1 German (L2 Dutch and English) and a control population (n = 53 in each group). Group comparisons and a Discriminant Analysis show that lexical diversity, sophistication and the distribution of items across the text in free speech are better predictors of group membership than formal tasks or elicited narratives. Extralinguistic factors, such as frequency of exposure and use or length of residence, have no predictive power for our results.

Influences of Previously Learned Languages on the Learning and Use of Additional Languages

This chapter provides an overview of existing research into the influence of previously learned languages on the learning and use of an additional language. This type of influence is explored from the perspectives of two separate but related types of effects: (1) the effects of simply knowing more than one language (whatever languages they may be) on the acquisition and use of a third or later language, and (2) the effects of the specific languages the learner knows. The former deals with what is commonly referred to as the cognitive consequences of bi- or multilingualism, whereas the latter deals with crosslinguistic influence. These effects and influences are described in general terms as well as in relation to the specific contexts of learning found in multilingual Spain. Emphasis is given especially to the ways these effects play out in classroom-based language learning—including CLIL programs—involving Basque-Spanish and Catalan-Spanish bilinguals learning English or other languages at school. The chapter maintains a multilingual perspective, recognizing the complex interplay of all of the languages the learners know, and it discusses both the directions of crosslinguistic influence as well as the factors that affect when, where, and to what degree such effects will emerge. The chapter concludes with interpretations regarding how CLIL programs might enhance the positive effects of prior language knowledge while minimizing its potential negative effects.

Communicative relevance: Color references in bilingual and trilingual speakers *

The study examined granularity of lexical partitioning of the blue area in speakers of English, which encodes the term blue; Russian, which encodes two terms, sinij [dark/navy blue] and goluboj [light/sky blue]; and Ukrainian, which encodes the terms synij [dark/navy blue] and blakytnyj and golubyj [light/sky blue]. Five groups of participants took part in the study: (1) 30 L1 speakers of English, (2) 30 L1 speakers of Russian, (3) 30 Russian–English bilinguals, (4) 30 English–Russian bilinguals, and (5) 25 Ukrainian–Russian–English trilinguals. Quantitative and qualitative analyses revealed that L1 Russian speakers referred to different types of blue significantly more frequently than all other groups, while bilinguals patterned with L1 English speakers. These findings suggest that classroom exposure to L2 Russian does not make the distinction between sinij and goluboj communicatively relevant for L1 English speakers and that everyday use of L2 English may trigger attrition of the contrast in L1 Russian.