Iambic Words Research Articles

Does Lexical Stress Pattern Affect Learning and Producing New Words in Greek for Children With Cochlear Implants?

Τhe lexical stress pattern (trochaic vs. iambic) may affect various aspects of word learning and word production in children with cochlear implants (CIs). This study aimed to investigate lexical stress effects in word learning by Greek-speaking children with CIs. A word learning paradigm, consisting of a word production and a word identification task, was used. A test list of eight pairs of disyllabic nonwords with identical phonological composition and contrasting lexical stress (eight trochaic and eight iambic), along with their referent pictured objects, was constructed and administered to 22 Greek-speaking children with CIs (ages 4;6-12;3 [years;months]) with normal nonverbal IQ and to 22 age-matched controls with normal hearing (NH) and no other difficulties. Overall, children with CIs exhibited lower performance than their hearing peers in all word-learning tasks, regardless of lexical stress pattern. Specifically, they identified significantly fewer words and exhibited significantly lower accuracy in word production than those of the controls. In the group with CIs, lexical stress pattern affected their production of words but not their word identification. Children with CIs showed more accurate production of iambic than trochaic words, a fact attributed to better vowel production. Yet, production of stress was less accurate for iambic than for trochaic words. Μoreover, stress assignment of iambic words was highly correlated with speech and language tests in children with CIs. Greek children with CIs exhibited lower performance in the word-learning task administered than children with NH did. In addition, the performance of children with CIs indicated a dissociation between the perception and production mechanisms and revealed complex relations between the segmental and prosodic aspects of words. Preliminary findings suggest that stress assignment in iambic words can serve as an indicator of speech and language growth.

Spanish input accelerates bilingual infants' segmentation of English words

We asked whether increased exposure to iambs, two-syllable words with stress on the second syllable (e.g., guitar), by way of another language – Spanish – facilitates English learning infants' segmentation of iambs. Spanish has twice as many iambic words (40%) compared to English (20%). Using the Headturn Preference Procedure we tested bilingual Spanish and English learning 8-month-olds' ability to segment English iambs. Monolingual English learning infants succeed at this task only by 11 months. We showed that at 8 months, bilingual Spanish and English learning infants successfully segmented English iambs, and not simply the stressed syllable, unlike their monolingual English learning peers. At the same age, bilingual infants failed to segment Spanish iambs, just like their monolingual Spanish peers. These results cannot be explained by bilingual infants' reliance on transitional probability cues to segment words in both their native languages because statistical cues were comparable in the two languages. Instead, based on their accelerated development, we argue for autonomous but interdependent development of the two languages of bilingual infants.

Rhythmic syncope and opacity in Mojeño Trinitario

This paper presents rhythmic syncope in Mojeño Trinitario, an Arawak language spoken in lowland Bolivia. In this language, every vowel that is in a weak prosodic position can syncopate. The syncope pattern of Mojeño Trinitario is remarkable for several reasons. First, it involves a regular, categorical and complete deletion rather than a statistical reduction of vowels. Second, it applies similarly to words with either of two stress patterns: iambic words, which make up the great majority of words, and trochaic ones, much less numerous. Third, a great variety of consonant sequences are the result of syncope, and syllabification applies again after syncope. Fourth, rhythmic syncope actually underapplies: almost half of the vowels that are in a position to syncopate are maintained, and vowel quality plays a statistical role in immunity to syncope. Fifth, due to a rich morphology and a set of complex phonotactic rules applying sequentially, syncope leads to extreme opacity. The data presented in this paper in a theory-neutral way contribute to the typology of rhythmic syncope. It will also be of interest to phonologists considering constraint-based vs. derivational models of phonology.

Reliability and stability of the metrical stress effect on segmental production accuracy in persons with apraxia of speech.

Acquired apraxia of speech (AOS) involves speech-production deficits on both the segmental and suprasegmental levels. Recent research has identified a non-linear interaction between the metrical structure of bisyllabic words and word-production accuracy in German speakers with AOS, with trochaic words (strong-weak stress) being resistant to errors compared with iambic words (weak-strong). To replicate previous findings in English speakers with AOS, to measure the test-retest reliability of the effect, and to examine the potential impact of different methods of word scoring. Speech samples were collected from 27 speakers with AOS and aphasia. Participants were at least 12 months post-stroke or penetrating brain injury, and represented a large range of AOS and aphasia severities. Productions were elicited via verbal model. Sampling was conducted on three separate occasions: the initial data-collection session and then repeated samplings at 1- and 4-week intervals. Bisyllabic words with a CVCVC segmental structure were selected. The list was divided into sublists representing differing lexical stress patterns: A list of 42 trochees, and one of 37 iambs. All speech samples were phonetically transcribed and then aligned with canonical transcriptions via an edit distance algorithm that followed transcription alignment principles. Phonetic-level errors (distortions) were penalized less severely than phonemic-level errors. Per cent consonants correct and whole-word accuracy were also examined. Trochee and iamb lists were analysed separately. Paired samples t-tests indicated that the modified edit distance was significantly lower for the trochee lists than for the iamb lists. There was a lack of a significant effect of time on the absolute difference between modified edit distance for both lists. Intraclass coefficients suggested the list and procedures used are appropriate as an outcome measure for group research. The results suggest that in English, as in German, the trochaic structure is more resistant to segmental errors in persons with AOS and aphasia, providing replication of the findings of Aichert etal. in 2016. Further, this effect is stable over repeated sampling occasions. Implications for clinical management of AOS include possible ways to scaffold item difficulty and potentially improve stimulus generalization.

Listeners’ perception of lexical stress in the first words of infants with cochlear implants and normally hearing infants

Normally hearing (NH) infants are able to produce lexical stress in their first words, but congenitally hearing-impaired children with cochlear implants (CI) may find this more challenging, given the limited transmission of spectro-temporal information by the implant. Acoustic research has shown that the acoustic cues to stress in the first words of Dutch-acquiring CI infants are less pronounced (Pettinato, De Clerck, Verhoeven, & Gillis, 2017). The present study investigates how listeners perceive lexical stress in the first words of CI and NH infants. Two research questions are addressed: (1) How successful are CI and NH children in implementing the prosodic cues to prominence? (2) Is the degree of stress in CI and NH words perceived to be similar?The stimuli used in this study are disyllabic words (n = 1089) produced by 9 infants with CI and 9 NH infants acquiring Dutch. The words were presented to adult listeners in a listening experiment, in which they assessed the stress pattern on a continuous visual analogue scale (VAS) which expresses to what extent syllables are perceived as stressed.The results show that listeners perceive typical word stress production in the first words of infants with CI. The words of CI and NH infants were rated in agreement with the target stress pattern as often, and trochaic words were rated more frequently as such than iambic words. Listeners more frequently perceive unstressed syllables in the first words of infants with CI. However, for the words that are perceived to be clearly stressed, the degree of word stress is comparable in the two groups, and both infant groups are perceived to produce more contrast between stressed and unstressed syllables in trochees than in iambs. It is concluded that that acoustic differences between CI and NH infants’ stress production are not necessarily perceptually salient.

Prosodic-structural modulation of stop voicing contrast along the VOT continuum in trochaic and iambic words in American English

This study explores the phonetic nature of phonological stop voicing contrast in American English by investigating how phonetic implementation of the voicing contrast is modulated by the prosodic structure along the continuum of phonetic voicing. In particular, the present study examines (1) the effects of two kinds of prosodic strengthening that can arise with prosodic structuring, a boundary-related domain-initial strengthening (DIS) and a prominence-induced strengthening, and (2) the possible enhancement types of linguistic contrasts that can underlie prosodic strengthening. The phonetic voicing was estimated using the Integrated Voicing Index (IVI), taking into account both the voicing lag (positive VOT) and the voiced interval during the closure. Results obtained with initial stops in both trochaic and iambic words are encapsulated as follows. Under the influence of DIS, both voiced and voiceless stops were produced with an increase in voicelessness, showing an enhancement of structurally motivated syntagmatic (CV) contrast. The effect size was larger for voiced stops, yielding a boundary-induced phonetic reduction of voicing contrast. Under the influence of prominence (focus), both voiced and voiceless stops showed an increase in voicelessness only in trochaic words, but this time, it was voiceless stops that showed a far greater effect, resulting in a maximization of voicing contrast—i.e., an enhancement of paradigmatic contrast. Moreover, the reduced voicing for voiced stops under prominence even in the medial position indicates that voiced stops are realized in reference to the phonetic feature {vl. unaspirated} rather than {voiced}. These findings imply that seemingly non-contrastive low-level variation is indeed systematically modulated by the prosodic structure in reference to phonetic representations that regulate the phonetic implementation of phonological contrast in a given language. An alternative account is also discussed in the framework of Articulatory Phonology.

Infant-directed speech reduces English-learning infants' preference for trochaic words.

Over the past couple of decades, research has established that (1) infant-directed speech (IDS) facilitates speech, language, and cognitive development; and (2) infants are sensitive to the rhythmic structures in the ambient language. However, little is known about the role of IDS in infants' processing of rhythmic structures. Building on these two lines of research, whether IDS enhances infants' sensitivity to the predominant stress pattern (trochaic) in English was asked. To address this question, 9-month-old American infants were familiarized and tested with both trochaic (e.g., lazy) and iambic (e.g., cartoon) words presented in either IDS or adult-directed speech (ADS). Infants showed listening preference for the trochaic over iambic words when the speech was presented in ADS, but not in IDS. These results suggest that IDS attenuates infants' preference for trochaic stress pattern. Further acoustical analyses demonstrated that IDS provided less salient spectral cues for the contrasts between stressed and unstressed syllables in trochaic words. These findings encourage further efforts to explore the effects of IDS on language acquisition from a broader perspective.

Overriding the Metrical Bias with Lexical Information: English-Learning 7.5-Month-Olds Use Mommy to Segment Iambic Words

ABSTRACTPrevious research shows that English-learning 7.5-month-olds are biased to segment speech at strong syllables consistent with the predominant trochaic (strong-weak) pattern of words in their language (Jusczyk, Houston, & Newsome, 1999). The present study asked whether 7.5-month-olds can use a familiar name to override their metrical bias and segment iambic (weak-strong) words from natural speech. Infants were familiarized to passages containing weak-strong-weak sequences (guiTAR is) preceded by Mama/Mommy or an unfamiliar name. Infants were tested on iambic words (guiTAR in Experiments 1–2) or trochaic nonwords (TARis in Experiment 3). Segmentation occurred only for iambic words that were preceded by Mama/Mommy during familiarization. The presence of Mama/Mommy attenuated infants’ bias to treat strong-syllables as word onsets. We suggest that young infants weight highly familiar words more strongly than metrical information and discuss the implications of this finding for a hierarchical model of segmentation that connects infant and adult segmentation systems.

Speech rhythm sensitivity and musical aptitude: ERPs and individual differences

This study investigated the electrophysiological markers of rhythmic expectancy during speech perception. In addition, given the large literature showing overlaps between cognitive and neural resources recruited for language and music, we considered a relation between musical aptitude and individual differences in speech rhythm sensitivity. Twenty adults were administered a standardized assessment of musical aptitude, and EEG was recorded as participants listened to sequences of four bisyllabic words for which the stress pattern of the final word either matched or mismatched the stress pattern of the preceding words. Words with unexpected stress patterns elicited an increased fronto-central mid-latency negativity. In addition, rhythm aptitude significantly correlated with the size of the negative effect elicited by unexpected iambic words, the least common type of stress pattern in English. The present results suggest shared neurocognitive resources for speech rhythm and musical rhythm.

Production of Lexical Stress in Non-Native Speakers of American English: Kinematic Correlates of Stress and Transfer

To assess the influence of second language (L2) proficiency on production characteristics of rhythmic sequences in the L1 (Bengali) and L2 (English), with emphasis on linguistic transfer. One goal was to examine, using kinematic evidence, how L2 proficiency influences the production of iambic and trochaic words, focusing on temporal and spatial aspects of prosody. A second goal was to assess whether prosodic structure influences judgment of foreign accent. Twenty Bengali-English bilingual individuals, 10 with low proficiency in English and 10 with high proficiency in English, and 10 monolingual English speakers, participated. Lip and jaw movements were recorded while the bilingual participants produced Bengali and English words embedded in sentences. Lower lip movement amplitude and duration were measured in trochaic and iambic words. Six native English listeners judged the nativeness of the bilingual speakers. Evidence of L1-L2 transfer was observed through duration but not amplitude cues. More proficient L2 speakers varied duration to mark iambic stress. Perceptually, the high-proficiency group received relatively higher native-like accent ratings. Trochees were judged as more native than iambs. Even in the face of L1-L2 lexical stress transfer, nonnative speakers demonstrated knowledge of prosodic contrasts. Movement duration appears to be more amenable than amplitude to modifications.

Language specific prosodic preferences during the first half year of life: Evidence from German and French infants

There is converging evidence that infants are sensitive to prosodic cues from birth onwards and use this kind of information in their earliest steps into the acquisition of words and syntactic regularities of their target language. Regarding word segmentation, it has been found that English-learning infants segment trochaic words by 7.5 months of age, and iambic words only by 10.5 months of age [Jusczyk, P. W., Houston, D. M., & Newsome, M. (1999). The beginnings of word segmentation in English-learning infants. Cognitive Psychology, 39, 159–207]. The question remains how to interpret this finding in relation to results showing that English-learning infants develop a preference for trochaic over iambic words between 6 and 9 months of age [Jusczyk, P. W., Cutler, A., & Redanz, N. (1993). Preference for the predominant stress patterns of English words. Child Development, 64, 675–687]. In the following, we report the results of four experiments using the headturn preference procedure (HPP) to explore the trochaic bias issue in German- and French-learning infants. For German, a trochaic preference was found at 6 but not at 4 months, suggesting an emergence of this preference between both ages (Experiments 1 and 2). For French, 6-month-old infants did not show a preference for either stress pattern (Experiment 3) while they were found to discriminate between the two stress patterns (Experiment 4). Our findings are the first to demonstrate that the trochaic bias is acquired by 6 months of age, is language specific and can be predicted by the rhythmic properties of the language in acquisition. We discuss the implications of this very early acquisition for our understanding of the emergence of segmentation abilities.

Prosodic patterns in Hebrew child-directed speech

The study examines prosodic characteristics of Hebrew speech directed to children between 0 ; 9-3 ; 0 years, based on longitudinal samples of 228,946 tokens (8,075 types). The distribution of prosodic patterns - the number of syllables and stress patterns - is analyzed across three lexical categories, distinguishing not only between open- and closed-class items, but also between these two categories and a third, innovative, class, referred to as between-class items. Results indicate that Hebrew CDS consists mainly of mono- and bisyllabic words, with differences between lexical categories; and that the most common stress pattern is word-final, with parallel distributions found for all categories. Additional analyses showed that verbs take word-final stress, but nouns are both trochaic and iambic. Finally, a developmental analysis indicates a significant increase in the number of iambic words in CDS. These findings have clear implications regarding the use of prosody for word segmentation and assignment of lexical class in infancy.

F2 variation in Newcastle and Leeds English liquid systems

In this paper we present a production study designed to explore the relationship between three observations which have previously been made about liquids in British English: first, that laterals have prosodically-determined ‘clear’ (syllable-initial) and ‘dark’ (syllable-final) variants; second, that some varieties of English have either clear [1] in all positions or dark [l] in all positions; third, that some varieties with clear [1] have dark [r] while some varieties with dark [1] have clear [r] (in broad phonetic transcription). We take F2 as an acoustic correlate of clearness/darkness and report on F2 variation in two representative varieties of British English, one which has clear initial [1] (Newcastle-upon-Tyne) and one with dark initial [1] (Leeds). We show that Newcastle English has higher F2 frequencies in [1] than in [r] and that the reverse pattern is found in Leeds English. These patterns can also be found in adjacent unstressed vowels but not in adjacent stressed vowels. Final [1] in both varieties has a lower F2 than initial [1]. In intervocalic contexts, these F2 distinctions in the liquids are observed in iambic words for both varieties. In trochaic words they are observed for Leeds only, though the vowel effects can be observed in both varieties. We discuss some phonological consequences of these findings.

Learning to Learn: Infants' Acquisition of Stress-Based Strategies for Word Segmentation

A majority of English words are stressed on their first syllable. Infants use stress as a cue to word segmentation, but it is unclear how infants discover the correlation between stress and word boundaries. We exposed English-learning infants to a list of words stressed on their second syllable to discover whether infants can learn a new relation between stress and word boundaries. English-learning infants treat stressed syllables as word onsets, which is incorrect in words where stressed syllables occur second (iambic words). A brief exposure allowed infants to subsequently segment iambic words correctly, whether the exposure consisted of 100% or 80% iambic words. We also trained 7-month-olds—who typically rely on transitional probabilities—to use stress as a cue to word segmentation. The results suggest that infants are sensitive to the distribution of stress across word position and that altering this distribution affects their segmentation strategies.

Learning to Learn: Infants’ Acquisition of Stress-Based Strategies for Word Segmentation

A majority of English words are stressed on their first syllable. Infants use stress as a cue to word segmentation, but it is unclear how infants discover the correlation between stress and word boundaries. We exposed English-learning infants to a list of words stressed on their second syllable to discover whether infants can learn a new relation between stress and word boundaries. English-learning infants treat stressed syllables as word onsets, which is incorrect in words where stressed syllables occur second (iambic words). A brief exposure allowed infants to subsequently segment iambic words correctly, whether the exposure consisted of 100% or 80% iambic words. We also trained 7-month-olds—who typically rely on transitional probabilities—to use stress as a cue to word segmentation. The results suggest that infants are sensitive to the distribution of stress across word position and that altering this distribution affects their segmentation strategies.

The Influence of Utterance Position on Children’s Production of Lexical Stress

Previous studies reporting acoustical data on children’s production of lexical stress examined words produced in isolation (i.e., with no carrier phrase) or in utterance-final position. In such contexts, the final syllable of the words being examined was also the utterance-final syllable. Syllables produced in utterance-final position are known to be longer in duration and lower in intensity and F₀ compared to other syllables within utterances. Therefore, utterance-final effects may have obscured previous results on children’s production of stress. Twenty children at approximately 6 years of age produced novel trochaic and iambic words in utterance-final and utterance-non-final position. Comparing productions across the two utterance positions suggested that reliance upon the utterance-final context was a confounding factor in past studies. Utterance-final position facilitated the iambic pattern of duration (short-long) and the trochaic pattern of intensity and F₀ (high-low). Utterance position sometimes affected trochees differently than iambs, especially in the duration of word-final syllables. The results are discussed in terms of past explanations of utterance position effects on acoustic characteristics of syllables.

Mapping of prosodic structure onto words and phrases in children's and adults' speech production

Direct recordings of lip and jaw movement were obtained to investigate how children and adults differentiate prosodic structure both within iambic and trochaic words and across word boundaries. It was hypothesised that children, especially those with less language skills, would be particularly likely to produce strong-weak (or trochaic) sequences. This experiment examined children's (both normally developing and specifically language impaired, aged 4–6 years) and adults’ productions of prosodic sequences that were controlled for syntactic and phonetic content, but that differed in rhythmic alternations, both within words (i. e., iambs vs. trochees) and across words (i. e., optimal strong-weak vs. stress gap or stress clash). To avoid final position effects, target words were in utterance internal position. Analyses included kinematic measures of prosodic structure (i. e., amplitude and duration of movements in weak vs. strong syllables; ratios of weak-to-strong movements). Consistent with prior work, weak syllables in iambs were produced differentially from those in trochees; though these effects were now observed in utterance position. However, in noun-noun sequences within a phrase, even when the rhythm rule was violated, prosodic foot structure was not reorganised as a function of rhythmic properties of the utterance. Overall, children with the least mature language skills demonstrated poor control of temporal and amplitude aspects of movement, especially in weak syllables. Findings are related to the organisation of speech production units across prosodic levels.

English-Learning Infants' Representations of Word Forms With Iambic Stress.

Retaining detailed representations of unstressed syllables is a logical prerequisite for infants' use of probabilistic phonotactics to segment iambic words from fluent speech. The head-turn preference study was used to investigate the nature of English-learners' representations of iambic word onsets. Fifty-four 10.5-month-olds were familiarized to passages containing the nonsense iambic word forms ginome and tupong. Following familiarization, infants were either tested on familiar (ginome and tupong) or near-familiar (pinome and bupong) versus unfamiliar (kidar and mafoos) words. Infants in the familiar test group (familiar vs. unfamiliar) oriented significantly longer to familiar than unfamiliar test items, whereas infants in the near-familiar test group (near-familiar vs. unfamiliar) oriented equally long to near-familiar and unfamiliar test items. Our results provide evidence that infants retain fairly detailed representations of unstressed syllables and therefore support the hypothesis that infants use phonotactic cues to find words in fluent speech.

Durational characteristics of the first productions of novel trochees and iambs in children with and without speech delay

The durational characteristics of novel words produced in repeated trials were evaluated in separate groups of children with, and without speech delay (SD). Children produced disyllabic novel words containing either a trochaic or iambic stress pattern. Results of acoustic analysis indicated a significant interaction between trial number and speaker group. The duration of words produced by children without SD decreased more abruptly across successive trials as compared to children with SD. In addition, duration decreased at a faster rate for trochaic words as compared to iambic words in both groups. Variability of word duration was greater in iambs than trochees. The results are discussed in terms of speech motor learning patterns that may underlie difficulties associated with SD.

Ictus and Accent - Philip Whaley Harsh: Iambic Words and Regard for Accent in Plautus. (Stanford University Publications, Language and Literature, Vol. VII, No. 2). Pp. 149. Stanford, California; Stanford University Press (London: Oxford University Press), 1949. Paper, $2.50.

Ictus and Accent - Philip Whaley Harsh: Iambic Words and Regard for Accent in Plautus. (Stanford University Publications, Language and Literature, Vol. VII, No. 2). Pp. 149. Stanford, California; Stanford University Press (London: Oxford University Press), 1949. Paper, $2.50. - Volume 1 Issue 1