Nivja H. De Jong

Praat script to detect syllable nuclei and measure speech rate automatically

In this article, we describe a method for automatically detecting syllable nuclei in order to measure speech rate without the need for a transcription. A script written in the software program Praat (Boersma & Weenink, 2007) detects syllables in running speech. Peaks in intensity (dB) that are preceded and followed by dips in intensity are considered to be potential syllable nuclei. The script subsequently discards peaks that are not voiced. Testing the resulting syllable counts of this script on two corpora of spoken Dutch, we obtained high correlations between speech rate calculated from human syllable counts and speech rate calculated from automatically determined syllable counts. We conclude that a syllable count measured in this automatic fashion suffices to reliably assess and compare speech rates between participants and tasks.

The morphological family size effect and morphology

It has been reported that in visual lexical decision response latencies to simplex nouns are shorter when these nouns have large morphological families, i.e., when they appear as constituents in large numbers of derived words and compounds. This study presents the results of four experiments that show that verbs have a Family Size effect independently of nominal conversion alternants, that this effect is a strict type frequency effect andnot a token frequency effect, that the effect is co-determined by the morphological structure of the inflected verb, and that it occurs irrespective of the orthographic shape of the base word.

Facets of Speaking Proficiency.

This study examined the componential structure of second-language (L2) speaking proficiency. Participants—181 L2 and 54 native speakers of Dutch—performed eight speaking tasks and six tasks tapping nine linguistic skills. Performance in the speaking tasks was rated on functional adequacy by a panel of judges and formed the dependent variable in subsequent analyses (structural equation modeling). The following independent variables were assessed separately: linguistic knowledge in two tests (vocabulary and grammar); linguistic processing skills (four reaction time measures obtained in three tasks: picture naming, delayed picture naming, and sentence building); and pronunciation skills (speech sounds, word stress, and intonation). All linguistic skills, with the exception of two articulation measures in the delayed picture naming task, were significantly and substantially related to functional adequacy of speaking, explaining 76% of the variance. This provides substantial evidence for a componential view of L2 speaking proficiency that consists of language-knowledge and language-processing components. The componential structure of speaking proficiency was almost identical for the 40% of participants at the lower and the 40% of participants at the higher end of the functional adequacy distribution (n = 73 each), which does not support Higgs and Clifford’s (1982) relative contribution model, predicting that, although L2 learners become more proficient over time, the relative weight of component skills may change.

What Makes Speech Sound Fluent? The Contributions of Pauses, Speed and Repairs.

The oral fluency level of an L2 speaker is often used as a measure in assessing language proficiency. The present study reports on four experiments investigating the contributions of three fluency aspects (pauses, speed and repairs) to perceived fluency. In Experiment 1 untrained raters evaluated the oral fluency of L2 Dutch speakers. Using specific acoustic measures of pause, speed and repair phenomena, linear regression analyses revealed that pause and speed measures best predicted the subjective fluency ratings, and that repair measures contributed only very little. A second research question sought to account for these results by investigating perceptual sensitivity to acoustic pause, speed and repair phenomena, possibly accounting for the results from Experiment 1. In Experiments 2–4 three new groups of untrained raters rated the same L2 speech materials from Experiment 1 on the use of pauses, speed and repairs. A comparison of the results from perceptual sensitivity (Experiments 2–4) with fluency perception (Experiment 1) showed that perceptual sensitivity alone could not account for the contributions of the three aspects to perceived fluency. We conclude that listeners weigh the importance of the perceived aspects of fluency to come to an overall judgment.

The processing and representation of Dutch and English compounds: Peripheral morphological, and central orthographic effects

In this study, we use the association between various measures of the morphological family and decision latencies to reveal the way in which the components of Dutch and English compounds are processed. The results show that for constituents of concatenated compounds in both languages, a position-related token count of the morphological family plays a role, whereas English open compounds show an effect of a type count, similar to the effect of family size for simplex words. When Dutch compounds are written with an artificial space, they reveal no effect of type count, which shows that the differential effect for the English open compounds is not superficial. The final experiment provides converging evidence for the lexical consequences of the space in English compounds. Decision latencies for English simplex words are better predicted from counts of the morphological family that include concatenated and hyphenated but not open family members.

Linguistic skills and speaking fluency in a second language

This study investigated how individual differences in linguistic knowledge and processing skills relate to individual differences in speaking fluency. Speakers of Dutch as a second language (N = 179) performed eight speaking tasks, from which several measures of fluency were derived such as measures for pausing, repairing, and speed (mean syllable duration). In addition, participants performed separate tasks, designed to gauge individuals’ second language linguistic knowledge and linguistic processing speed. The results showed that the linguistic skills were most strongly related to average syllable duration, of which 50% of individual variance was explained; in contrast, average pausing duration was only weakly related to linguistic knowledge and processing skills.

Dutch Inflection: The Rules that Prove the Exception

This chapter addresses the balance of storage and computation in the mental lexicon for fully regular and productive inflectional processes in Dutch. We present evidence that both regular inflected nouns and regular inflected verbs show clear and robust effects of storage, but that at the same time on-line parsing also plays a role. We argue that the balance of storage and computation cannot be predicted on the basis of economy of linguistic description. Instead, a range of cognitive and linguistic factors are crucial determinants.

Native speakers' perceptions of fluency and accent in L2 speech

Oral fluency and foreign accent distinguish L2 from L1 speech production. In language testing practices, both fluency and accent are usually assessed by raters. This study investigates what exactly native raters of fluency and accent take into account when judging L2. Our aim is to explore the relationship between objectively measured temporal, segmental and suprasegmental properties of speech on the one hand, and fluency and accent as rated by native raters on the other hand. For 90 speech fragments from Turkish and English L2 learners of Dutch, several acoustic measures of fluency and accent were calculated. In Experiment 1, 20 native speakers of Dutch rated the L2 Dutch samples on fluency. In Experiment 2, 20 different untrained native speakers of Dutch judged the L2 Dutch samples on accentedness. Regression analyses revealed, first, that acoustic measures of fluency were good predictors of fluency ratings. Second, segmental and suprasegmental measures of accent could predict some variance of accent ratings. Third, perceived fluency and perceived accent were only weakly related. In conclusion, this study shows that fluency and perceived foreign accent can be judged as separate constructs.

Semantic and phonological context effects in speech error repair.

When speakers repair speech errors, they plan the repair in the context of an abandoned word (the error) that is usually similar in meaning or form. Two picture-naming experiments tested whether the errors lexical representations influence repair planning. Context pictures were sometimes replaced with target pictures; the picture names were related in meaning or form or were unrelated. The authors measured target picture-naming latencies separately for trials in which the context name was interrupted or completed. Interrupted trials showed semantic interference and phonological facilitation, whereas completed trials showed semantic facilitation and phonological interference. Thus, errors influence repair production. The authors explain the polarity of these effects in terms of the literature on context effects in word production.

Linguistic competences of learners of Dutch as a second language at the B1 and B2 levels of speaking proficiency of the Common European Framework of Reference for Languages (CEFR)

This study examines the associations between the speaking proficiency of 181 adult learners of Dutch as a second language and their linguistic competences. Performance in eight speaking tasks was rated on a scale of communicative adequacy. After extrapolation of these ratings to the Overall Oral Production scale of the Common European Framework of Reference for Languages (CEFR) (Council of Europe, 2001), 80 and 30 participants (on average per speaking task) were found to be, respectively, at the B1 and B2 levels of this scale. The following linguistic competences were tapped with non-communicative tasks: productive vocabulary knowledge, productive knowledge of grammar, speed of lexical retrieval, speed of articulation, speed of sentence building, and pronunciation skills. Discriminant analyses showed that all linguistic competences, except speed of articulation, discriminated participants at the two levels of oral production. Subsequent comparisons showed that the distance between B1ers and B2ers was smaller in knowledge of high-frequency words than in knowledge of medium- and low-frequency words. Extrapolation from scores on the vocabulary test yielded estimations of productive vocabularies of, on average, 4000 and 7000 words for B1ers and B2ers, respectively. The grammar test assessed grammatical knowledge in 10 domains. B2ers were found to outperform B1ers on all parts of the test. Thus, the differences in lexical and grammatical knowledge of B1ers and B2ers appear to be a matter of degree, rather than a matter of category or domain. The paper ends with a research agenda for a linguistic underpinning of the CEFR.