Exploring the effect of lexicality and listener experience on gradient ratings of Swedish sibilant fricatives.

This study explores the influence of lexicality on gradient judgments of Swedish sibilant fricatives by contrasting ratings of initial fricatives in words and word fragments (initial CV-syllables). Visual-Analogue Scale (VAS) judgments were elicited from experienced listeners (speech-language pathologists; SLPs) and inexperienced listeners, and compared with respect to the effects of lexicality using Bayesian mixed-effects beta regression. Overall, SLPs had higher intra- and interrater reliability than inexperienced listeners. SLPs as a group also rated fricatives as more target-like, with higher precision, than did inexperienced listeners. An effect of lexicality was observed for all individual listeners, though the magnitude of the effect varied. Although SLP's ratings of Swedish children's initial voiceless fricatives were less influenced by lexicality, our results indicate that previous findings concerning VAS ratings of non-lexical CV-syllables cannot be directly transferred to the clinical context, without consideration of possible lexical bias.

Listening like a speech-training app: Expert and non-expert listeners' goodness ratings of children's speech.

Speech training apps are being developed that provide automatic feedback concerning children's production of known target words, as a score on a 1-5 scale. However, this 'goodness' scale is still poorly understood. We investigated listeners' ratings of 'how many stars the app should provide as feedback' on children's utterances, and whether listener agreement is affected by clinical experience and/or access to anchor stimuli. In addition, we explored the association between goodness ratings and clinical measures of speech accuracy; the Percentage of Consonants Correct (PCC) and the Percentage of Phonemes Correct (PPC). Twenty speech-language pathologists and 20 non-expert listeners participated; half of the listeners in each group had access to anchor stimuli. The listeners rated 120 words, collected from children with and without speech sound disorder. Concerning reliability, intra-rater agreement was generally high, whereas inter-rater agreement was moderate. Access to anchor stimuli was associated with higher agreement, but only for non-expert listeners. Concerning the association between goodness ratings and the PCC/PPC, correlations were moderate for both listener groups, under both conditions. The results indicate that the task of rating goodness is difficult, regardless of clinical experience, and that access to anchor stimuli is insufficient for achieving reliable ratings. This raises concerns regarding the 1-5 rating scale as the means of feedback in speech training apps. More specific listener instructions, particularly regarding the intended context for the app, are suggested in collection of human ratings underlying the development of speech training apps. Until then, alternative means of feedback should be preferred.

Parent rating of intelligibility: A discussion of the construct validity of the Intelligibility in Context Scale (ICS) and normative data of the Swedish version of the ICS.

BACKGROUND: Intelligibility can be defined as the speakers' ability to convey a message to the listener and it is considered the key functional measure of speech. The Intelligibility in Context Scale (ICS) is a parent rating scale used to assess intelligibility in children. AIMS: To describe normative and validation data on the ICS in Swedish and to investigate how these are related to age, gender and multilingualism. METHODS & PROCEDURES: Two studies were included. Study 1 included ICS forms from 319 Swedish-speaking children (3:2-9:2 years:months). Study 2 included video recordings and ICS forms from 14 children with speech sound disorder (SSD) and two with typical speech. The video recordings were transcribed in the validation process, resulting in intelligibility reference scores to which ICS scores were correlated. OUTCOMES & RESULTS: Study 1: The mean value of the ICS for the 319 children was 4.73. There were no differences in ICS score related to age or gender. The children in the multilingual group were significantly older than the monolingual group and had significantly lower ICS scores than the group of monolinguals. Study 2: There was a moderate correlation between the ICS score and the transcription-based intelligibility score, with the two children with typical speech excluded; however, this correlation was not significant. CONCLUSIONS & IMPLICATIONS: We contribute mean scores and percentiles on the ICS for Swedish-speaking children. The finding that the ICS does not provide valid measures of intelligibility for the included children with SSD suggests that the instrument measures a different construct. WHAT THIS PAPER ADDS: What is already known on the subject The ICS has been translated to numerous languages and validated against articulation measures in several previous studies. The validity of the Swedish version has been investigated against intelligibility based on transcription of single words. What this paper adds to existing knowledge The study provides normative values of the Swedish version of the ICS for children aged 3-9 years. This is the first study to use a gold standard measure of intelligibility in continuous speech to validate the ICS. The results show a somewhat dubious validity regarding ICS for the group of children with SSD included in the study. What are the potential or actual clinical implications of this work? The ICS's suitability as a measure of intelligibility is questionable; however, it might be of use for speech and language pathologists to give an overview of the parents' view of their child's ability to communicate, in order to make a decision on possible further assessment and intervention. The normative values of the Swedish version of the ICS could be of use in this decision process.

Towards an Integrated Curriculum in a Speech and Language Pathology Education Programme: Development and Constituents' Initial Responses.

BACKGROUND: A traditional curricular structure may challenge integration between foundational and clinical sciences in speech and language pathology (SLP) education. This project aimed to increase curriculum integration at a Swedish SLP education programme. METHODS: Learning outcomes in the existent curriculum were copied from their original courses and re-structured with reference to vertical tracks, in order to address them within and across years of study. A content analysis of interviews with teachers and students was conducted for the evaluation of curricular change. RESULTS: Among the changes were earlier introduction to clinical science and revisiting of foundational sciences later in the education. Theme concepts were defined to scaffold horizontal integration, whereas revisited use of documented material was formalized to ensure vertical integration. In evaluation interviews, multiple examples were provided of how the new curriculum was perceived as being more integrated, with horizontal themes and vertical tracks providing structure. Concerns raised highlight the importance of appointing clear responsibilities. CONCLUSIONS: The concepts "gaps" and "overlaps" may guide remediation of areas where increased curricular integration is warranted. Serial child observations running through the curriculum may provide a platform for both horizontal and vertical integration. For maintenance of curricular integration, clear responsibilities are needed, stretching across course and semester boundaries.

Dealing with the unknown - addressing challenges in evaluating unintelligible speech.

When investigating the interaction between speech production and intelligibility, unintelligible speech portions are often of particular interest. Therefore, the fact that the standard quantification of speech production - the Percentage of Consonants Correct (PCC) - is only computed on intelligible speech is unsatisfying. Our purpose was to evaluate a new quantification of speech production: the Percentage of Intelligible and Correct Syllables (PICS) designed to address this limitation. A secondary purpose was to explore a task designed to elicit connected speech - concurrent commenting - offering more control of intended speech production compared to free conversation. Nine children with SSD participated in four speech elicitation tasks, varying with respect to ecological validity, and to degree of control: (1) word imitation, (2) picture naming, (3) concurrent commenting of a silent short video, and (4) free conversation. Speech accuracy was analysed in terms of PCC-Revised (PCC-R) and PICS, and intelligibility with regards to the Proportion of Intelligible Syllables (PINTS). A strong correlation was observed between PICS and PCC-R, supporting the construct validity of PICS. Further, a moderate correlation was seen between PICS and PINTS, presumably reflecting that these measures capture different - although related - constructs. No difference was seen between concurrent commenting and free conversation in terms of articulation proficiency or intelligibility; however, this needs further investigation based on more data. Nevertheless, we suggest concurrent commenting as a useful method for eliciting connected speech; in retaining more control over intended target words compared to free conversation, this task may be particularly useful in the context of unintelligible speech.

Subjective ratings of age-of-acquisition: exploring issues of validity and rater reliability.

This study aimed to investigate concerns of validity and reliability in subjective ratings of age-of-acquisition (AoA), through exploring characteristics of the individual rater. An additional aim was to validate the obtained AoA ratings against two corpora - one of child speech and one of adult speech - specifically exploring whether words over-represented in the child-speech corpus are rated with lower AoA than words characteristic of the adult-speech corpus. The results show that less than one-third of participating informants' ratings are valid and reliable. However, individuals with high familiarity with preschool-aged children provide more valid and reliable ratings, compared to individuals who do not work with or have children of their own. The results further show a significant, age-adjacent difference in rated AoA for words from the two different corpora, thus strengthening their validity. The study provides AoA data, of high specificity, for 100 child-specific and 100 adult-specific Swedish words.

Acoustic and perceptual evaluation of category goodness of /t/ and /k/ in typical and misarticulated children's speech.

This investigation explores perceptual and acoustic characteristics of children's successful and unsuccessful productions of /t/ and /k/, with a specific aim of exploring perceptual sensitivity to phonetic detail, and the extent to which this sensitivity is reflected in the acoustic domain. Recordings were collected from 4- to 8-year-old children with a speech sound disorder (SSD) who misarticulated one of the target plosives, and compared to productions recorded from peers with typical speech development (TD). Perceptual responses were registered with regards to a visual-analog scale, ranging from "clear [t]" to "clear [k]." Statistical models of prototypical productions were built, based on spectral moments and discrete cosine transform features, and used in the scoring of SSD productions. In the perceptual evaluation, "clear substitutions" were rated as less prototypical than correct productions. Moreover, target-appropriate productions of /t/ and /k/ produced by children with SSD were rated as less prototypical than those produced by TD peers. The acoustical modeling could to a large extent discriminate between the gross categories /t/ and /k/, and scored the SSD utterances on a continuous scale that was largely consistent with the category of production. However, none of the methods exhibited the same sensitivity to phonetic detail as the human listeners.

Children's perception of their synthetically corrected speech production.

We explore children's perception of their own speech - in its online form, in its recorded form, and in synthetically modified forms. Children with phonological disorder (PD) and children with typical speech and language development (TD) performed tasks of evaluating accuracy of the different types of speech stimuli, either immediately after having produced the utterance or after a delay. In addition, they performed a task designed to assess their ability to detect synthetic modification. Both groups showed high performance in tasks involving evaluation of other children's speech, whereas in tasks of evaluating one's own speech, the children with PD were less accurate than their TD peers. The children with PD were less sensitive to misproductions in immediate conjunction with their production of an utterance, and more accurate after a delay. Within-category modification often passed undetected, indicating a satisfactory quality of the generated speech. Potential clinical benefits of using corrective re-synthesis are discussed.

Children's recognition of their own recorded voice: influence of age and phonological impairment.

Children with phonological impairment (PI) often have difficulties perceiving insufficiencies in their own speech. The use of recordings has been suggested as a way of directing the child's attention toward his/her own speech, despite a lack of evidence that children actually recognize their recorded voice as their own. We present two studies of children's self-voice identification, one exploring developmental aspects, and one exploring potential effects of having a PI. The results indicate that children from 4 to 8 years recognize their recorded voice well (around 80% accuracy), regardless of whether they have a PI or not. A subtle change in this ability from 4 to 8 years is observed that could be linked to a development in short-term memory. Clinically, one can indeed expect an advantage of using recordings in therapy; this could constitute an intermediate step toward the more challenging task of online self-monitoring.

A survey of Swedish speech-language pathologists' practices regarding assessment of speech sound disorders.

PURPOSE: To explore Swedish clinical practice regarding assessment of suspected Speech Sound Disorders (SSD) in children. METHODS: A web-based questionnaire, regarding assessment of SSD in children 4;6-6;11 (years; months), was distributed to Swedish speech-language pathologists (SLPs) through social media and online forums. The questions concerned the frequency and manner of assessment for seven assessment components, chosen based on a review of international recommendations for SSD assessment. RESULTS: A total of 131 SLPs responded to the questionnaire. The results show that Swedish SSD assessment practices vary with regards to the frequency and manner of assessment for many components. Speech output is frequently assessed while speech perception, phonological awareness and oral-motor function are assessed less frequently. A variety of manners of assessment, for example, standardised tests, non-standardised material, and informal assessment procedures, such as observation, are utilized by respondents. CONCLUSIONS: Swedish SSD assessment practices are variable. The present paper reveals areas for development within SLP practice and education programmes, and provides a new perspective on present praxis with regards to the assessment of suspected SSD in Sweden.

Simulating Speech Error Patterns Across Languages and Different Datasets.

Children's speech acquisition is influenced by universal and language-specific forces. Some speech error patterns (or phonological processes) in children's speech are observed in many languages, but the same error pattern may have different effects in different languages. We aimed to explore phonological effects of the same speech error patterns across different languages, target audiences and discourse modes, using a novel method for large-scale corpus investigation. As an additional aim, we investigated the face validity of five different phonological effect measures by relating them to subjective ratings of assumed effects on intelligibility, as provided by practicing speech-language pathologists. Six frequently attested speech error patterns were simulated in authentic corpus data: backing, fronting, stopping, /r/-weakening, cluster reduction and weak syllable deletion-each simulation resulting in a "misarticulated" version of the original corpus. Phonological effects were quantified using five separate metrics of phonological complexity and distance from expected target forms. Using Swedish child-speech data as a reference, phonological effects were compared between this reference and a) child speech in Norwegian and English, and b) data representing different modes of discourse (spoken/written) and target audiences (adults/children) in Swedish. Of the speech error patterns, backing-the one atypical pattern of those included-was found to cause the most detrimental effects, across languages as well as across modes and speaker ages. However, none of the measures reflects intuitive rankings as provided by clinicians regarding effects on intelligibility, thus corroborating earlier reports that phonological competence is not translatable into levels of intelligibility.

Canonical babbling ratio - Concurrent and predictive evaluation of the 0.15 criterion.

INTRODUCTION: Canonical babbling ratio (CBR) is a commonly used measure to quantify canonical babbling (CB), and 0.15 is the commonly accepted criterion for the canonical babbling stage. However, this has not been thoroughly investigated. The aim of this study was to evaluate the validity of this criterion using concurrent and predictive comparisons. METHODS: Longitudinal data from 50 children recruited in different clinical projects were used. At 10 months of age, CBR was calculated based on counted utterances from audio-video recorded parent-child interactions. The videos were also assessed by CB observation, where an observer made an overall judgement on whether the child was in the canonical babbling stage or not. For the concurrent evaluation, CBR was compared to CB observation as a reference test, using area under the curve (AUC). The criterion resulting in the best combination of sensitivity and specificity was identified using positive likelihood ratios. In the predictive comparisons CBR was analyzed as a predictor of speech/language difficulties at 30-36 months. Participants presenting with difficulties in consonant production and/or parent-reported vocabulary were considered to have speech/language difficulties. Sensitivity and specificity were compared for CBR using the 0.15 criterion and the new criterion identified in this study. RESULTS: An AUC of 0.87 indicated that CBR is a valid measure of canonical babbling in 10-month-old children. The best combination of sensitivity and specificity was found at a criterion of 0.14 (sensitivity 0.96, specificity 0.70). In the predictive comparison, CBR with a 0.14 or 0.15 criterion revealed the same sensitivity (0.71) but 0.14 showed a slightly better specificity (0.52 versus 0.42). CONCLUSIONS: CBR is a valid measure of CB (at 10 months). However, when using CBR to classify children's babbling as canonical or non-canonical, researchers need to carefully consider the implications of the chosen criterion.

Measuring intelligibility in spontaneous speech using syllables perceived as understood.

PURPOSE: Intelligibility, the ability to convey a message by speech, is one of the most important variables in speech-language pathology. The assessment of intelligibility is a challenge especially when it comes to spontaneous speech. The aim of the study was to investigate validity and reliability of a method for assessment of intelligibility, syllables perceived as understood (SPU); a method that is more time-efficient than previous methods based on transcription, as it does not require a master transcript for reference. METHOD: A group of 20 adult listeners transcribed stimuli consisting of spontaneous speech from 16 children (14 with speech sound disorder and two with typical speech and language development, age 4:4 to 8:1, M = 6:0). Intelligibility was calculated based on these orthographic transcripts, as a) proportion of syllables perceived as understood (SPU) and b) proportion of syllables correctly understood (SCU), with reference to a master transcript. Validity was checked through investigation of the correlation and difference between these two measures. Reliability was analysed with inter-listener reliability by intra-class correlation. RESULTS: The correlation between SPU and SCU (the gold standard intelligibility score) was strong and statistically significant, with SPU being consistently higher than SCU. Inter-listener reliability for single measures of intra-class correlation of the assessment by syllables perceived as understood was moderate to low, whereas the inter-listener reliability for average measures of intra-class correlation was high. CONCLUSIONS: The method based on SPU might be used for assessment of intelligibility if the median from several listeners is used or when comparing results from the same listener over time. The SPU method might therefore be a valuable tool in a clinical and research context as a more valid option than rating scales and a more time-efficient method than the gold standard SCU method. However, it should be noted that the reliability of the SPU is not as high as for the SCU.

Speech and Language in 5-year-olds with Different Neurological Disabilities and the Association between Early and Later Consonant Production.

The primary aim was to describe speech and language abilities in a clinical group of verbal 5-year-old children diagnosed with neurological disability (ND) in infancy, and the secondary aim was to trace precursors to consonant production at age 5 years (T2) in data from 12 to 22 months (T1). The participants (n = 11, with Down syndrome (DS), cerebral palsy, and chromosomal deletion syndromes) were tested with a battery of speech and language tests. Consonant production at T2 was compared to data on consonant use at T1. At T2, two participants had age appropriate speech and language and another three had age-appropriate speech, but low results on language tests. The remaining six participants had severe speech and language difficulties. Participants with DS had significantly lower results on consonant production measures. An association between consonant production at T1 and T2 for participants with DS indicates that number of different true consonants might be a predictive measure when evaluating young children with DS.

Audience Response System-Based Evaluation of Intelligibility of Children's Connected Speech - Validity, Reliability and Listener Differences.

PURPOSE: We assessed audience response systems (ARS)-based evaluation of intelligibility, with a view to find a valid and reliable intelligibility measure that is accessible to non-trained participants. In addition, we investigated potential listener differences between pediatric speech and language pathologists (SLPs) and untrained adults. METHOD: Sixteen one-minute samples of connected speech were compiled, collected from 14 children with a speech sound disorder (SSD) and two children with typical speech. 16 SLPs and 13 untrained adults participated in a series of ARS listening sessions, where they were fitted with headphones and hand controls, and instructed to click a button whenever they did not understand the child speaking. Listeners' button clicks were registered and, for each speech sample, totaled into an (un)intelligibility index. The proportion of syllables perceived correctly - based on orthographic listener transcripts - was used as a reference score of intelligibility. RESULTS: The ARS-based intelligibility scores correlated strongly with the intelligibility reference score. Reliability was high across listener groups and weaker for single listeners. No significant difference was found between the evaluations of SLPs and untrained adults. CONCLUSIONS: ARS-based evaluation offers a valid and reliable measure of intelligibility of particular value in research as a practical tool for collecting input from listeners without experience or knowledge of SSDs. We stress that the ARS design presupposes a listener panel, and that evaluations obtained from individual listeners are predictably inadequate in terms of reliability.

Intelligibility of Children With Speech Sound Disorders Evaluated by Listeners With Swedish as a Second Language.

Purpose This study aimed to investigate the intelligibility of children's atypical speech in relation to listeners' language background. Method Forty-eight participants listened to and transcribed isolated words repeated by children with speech sound disorders. Participants were divided into, on the one hand, a multilingual group (n = 29) that was further divided into subgroups based on age of acquisition (early, 0-3 years; intermediate, 4-12 years; and late, > 12 years) and, on the other hand, a monolingual comparison group (n = 19). Results The monolingual listeners obtained higher intelligibility scores than the multilingual listeners; this difference was statistically significant. Participants who acquired Swedish at an older age (> 4 years) were found to have lower scores than other listeners. The later the age of acquisition, the less of the atypical speech was decoded correctly. A further analysis of the transcriptions also revealed a higher level of nonwords among the incorrect transcriptions of the multilinguals than that of the monolinguals who used more real words, whereas both groups were equally prone to using blanks when they did not perceive a word. Conclusions This indicates a higher risk of communicative problems between late acquirers of Swedish and children with speech sound disorders. Clinical implications, such as involving communication partners in the intervention process, are discussed as well as possible linguistic explanations to the findings. This study could be seen as a starting point in the field of research regarding the relations between the language background of the listener and the ability to perceive atypical speech.

Perceptual Detection of Subtle Dysphonic Traits in Individuals with Cervical Spinal Cord Injury Using an Audience Response Systems Approach.

OBJECTIVES: Reduced respiratory function following lower cervical spinal cord injuries (CSCIs) may indirectly result in vocal dysfunction. Although self-reports indicate voice change and limitations following CSCI, earlier efforts using global perceptual ratings to distinguish speakers with CSCI from noninjured speakers have not been very successful. We investigate the use of an audience response system-based approach to distinguish speakers with CSCI from noninjured speakers, and explore whether specific vocal traits can be identified as characteristic for speakers with CSCI. METHODS: Fourteen speech-language pathologists participated in a web-based perceptual task, where their overt reactions to vocal dysfunction were registered during the continuous playback of recordings of 36 speakers (18 with CSCI, and 18 matched controls). Dysphonic events were identified through manual perceptual analysis, to allow the exploration of connections between dysphonic events and listener reactions. RESULTS: More dysphonic events, and more listener reactions, were registered for speakers with CSCI than for noninjured speakers. Strain (particularly in phrase-final position) and creak (particularly in nonphrase-final position) distinguish speakers with CSCI from noninjured speakers. CONCLUSIONS: For the identification of intermittent and subtle signs of vocal dysfunction, an approach where the temporal distribution of symptoms is registered offers a viable means to distinguish speakers affected by voice dysfunction from non-affected speakers. In speakers with CSCI, clinicians should listen for presence of final strain and nonfinal creak, and pay attention to self-reported voice function and voice problems, to identify individuals in need for clinical assessment and intervention.