Conspiring simplification strategies of [Obstruent+Liquid] clusters in a case study of child Greek: emergence of the marked.

This paper addresses the idiosyncratic cluster simplification patterns observed in a child with disordered phonological development, who is acquiring Greek. The child has mastered word-internal and word-final codas and clusters of reversed sonority. However, the child does not realise the target well-formed tautosyllabic [Obstruent+Liquid] clusters with rising sonority. The child's system requires a single onset with maximum sonority dispersion between the onset and the syllable nucleus. As a result, cluster simplification occurs, via reduction to the less sonorous Obstruent - the most prevalent reduction pattern cross-linguistically. However, at the same time, the grammar requires faithful realisation of the target segment number. This requirement is fulfiled through two distinct conspiring metathesis patterns, distributed complementarily, resulting in the realisation of marked structures. The patterns depend on the position of the cluster within the target word. In word internal position, a compensatory metathesis of the Liquid takes place in the preceding syllable coda. In word initial position, the Manner of Articulation of the metathesised Liquid is delinked, while its Coronal Place of Articulation is faithfully preserved, and is realised by default as a Coronal Sibilant [s]. The latter Sibilant is attached as an appendix to the syllable node at the word left-edge. We argue that, in the grammar of this child, there is a-synchronisation between the development of the prosodic word layer and the development of syllable layer. Specifically, a-synchronisation is evident in the development of the (branching) onset syllabic subconstituent.

Vocal and early speech development in Korean-acquiring children with hearing loss and typical hearing.

This study investigated the vocal and early speech development of Korean-acquiring children with hearing loss (HL) who underwent early auditory amplification compared to their typical hearing (TH) counterparts. The research focused on phonological characteristics of child vocalisation based on samples collected from naturalistic home environments. One-day home recordings using a Language ENvironment Analysis (LENA) recorder were obtained from 6 children with HL and 12 children with TH who ranged from 17 to 23 months of age in Korean monolingual environments. Child volubility, canonical babbling ratio (CBR), consonant distributions, and utterance structures of vocalisations were evaluated through qualitative and quantitative analyses of vocalisation samples collected from LENA recordings. The findings revealed that children with HL displayed comparable vocalisation levels to children with TH, with no significant differences in volubility and CBR. In consonant and utterance shape inventories, noticeable quantitative and qualitative differences were observed between children with HL and those with TH. The study also suggested both universal and language-specific production patterns, revealing the early effects of ambient language on consonant distributions and utterance structures within their vocalisation repertoire. This study emphasised the role of auditory input and the importance of early auditory amplification to support speech development in children with HL.

Talker variability is not always the right noise: 14 month olds struggle to learn dissimilar word-object pairs under talker variability conditions.

Seminal work by Stager & Werker (1997) finds that 14-month-olds can rapidly learn two word-object pairings if the words are distinct (e.g. "neem" and "lif") but not similar (e.g. the minimal pair "bih" and "dih"). More recently, studies have found that adding talker variability during exposure to new word-object pairs lets 14-month-olds succeed on the more challenging minimal pair task, presumably due to talker variability highlighting the "relevant" consistencies between the similar words (Rost & McMurray, 2009; Galle et al., 2015; Hohle et al., 2020). It remains an open question, however, whether talker variability would be similarly useful for learning new word-object pairings when the words themselves are already distinct, or whether instead this extra variability may extinguish learning due to increased task demands. We find evidence for the latter. Namely, in our sample of 54 English-learning 14-month-olds, training infants on two word-object pairings (e.g. "neem" with a dog toy and "lof" with a kitchen tool) only led them to notice when the words and objects were switched if they were trained with single-speaker identical word tokens. When the training featured talker variability (from one or multiple talkers) infants failed to learn the pairings. We suggest that when talker variability is not necessary to highlight the invariant differences between similar words, it may actually increase task difficulty, making it harder for infants to determine what to attend to in the earliest phases of word learning.

Singleton consonant onset acquisition in monolingual Granada Spanish-speaking preschoolers with typical versus protracted phonological development: Impacts of word structure and feature constraints.

While consonant acquisition clearly requires mastery of different articulatory configurations (segments), sub-segmental features and suprasegmental contexts influence both order of acquisition and mismatch (error) patterns (Bérubé, Bernhardt, Stemberger & Ciocca, 2020). Constraints-based nonlinear phonology provides a comprehensive framework for investigating the impact of sub- and suprasegmental impacts on acquisition (Bernhardt & Stemberger, 1998). The current study adopted such a framework in order to investigate these questions for Granada Spanish. Single-word samples of monolingual preschoolers in Granada (29 typically developing; 30 with protracted phonological development) were transcribed by native Spanish speakers in consultation with an international team. Beta regression analyses showed significant effects of age, developmental group, and word structure variables (word length, stress, position of consonants and syllables within the word); salience, markedness and/or frequency across the phonological hierarchy accounted for many patterns. The study further demonstrates the impacts of sub- and suprasegmental constraints of the phonological system on consonant acquisition.

Child phonological responses to variegation in adult words: A cross-linguistic study.

Variegation - the presence of more than one supraglottal consonant per word - is a key challenge for children as they increase their expressive vocabulary toward the end of the single-word period. Here we consider the prosodic structures of target words and child forms in English, Finnish, French, Japanese and Mandarin to determine whether children learning these languages respond similarly to the challenge or instead differ in ways related to the phonological structure of the adult language. Based on proportional occurrence of each structure, we find that the word forms of children learning Mandarin and Japanese show more variegation than do those of children learning the European languages, although their target words do not; proportions of reduplication, consonant harmony and single-consonant words also differ by language. We conclude that experience with the structure of the language - and thus representation, as well as immature articulatory skills - shapes children's responses to variegation.

Acquisition of the feature [+spread glottis] in Icelandic.

The feature [+spread glottis] ([+s.g.]) denotes that a speech sound is produced with a wide glottal aperture with audible voiceless airflow. Icelandic is unusual in the degree to which [+spread glottis] is involved in the phonology: in /h/, pre-aspirated and post-aspirated stops, voiceless fricatives and voiceless sonorants. The ubiquitousness of the feature could potentially affect the rate and process of its acquisition. This paper investigates the development of [+s.g.] in Icelandic, both in general and in a range of contexts, in a cross-sectional study of 433 typically developing Icelandic-speaking children aged two to seven years. As a feature, [+s.g.] is acquired early in Icelandic, although specific sound classes lag behind due to other output constraints. Children reach mastery of [+s.g.] by age three except in word-initial post-aspirated stops and voiceless nasals. Findings are interpreted in light of the literature on the feature and its development.

Literacy and early language development: Insights from computational modelling.

Computational models of reading have tended to focus on the cognitive requirements of mapping among written, spoken, and meaning representations of individual words in adult readers. Consequently, the alignment of these computational models with behavioural studies of reading development has to date been limited. Models of reading have provided us with insights into the architecture of the reading system, and these have recently been extended to investigate literacy development, and the early language skills that influence children's reading. These models show us: how learning to read builds on early language skills, why various reading interventions might be more or less effective for different children, and how reading develops across different languages and writing systems. Though there is growing alignment between descriptive models of reading behaviour and computational models, there remains a gap, and I lay out the groundwork for how translation may become increasingly effective through future modelling work.

Acquisition of variability in Akan Phonology: Labio-palatalized consonants and front rounded vowels.

This paper addresses how input variability in the adult phonological system is mastered in the output of young children in Akan, a Kwa language spoken in Ghana, involving variability between labio-palatalized consonants and front rounded vowels. The high-frequency variant involves a complex consonant which is expected to be mastered late, while the low-frequency variant involves a front rounded vowel which is expected to be mastered relatively early. Late mastery of complex consonants was confirmed. The high-frequency labiopalatalized-consonant variant was absent at age 3 and not yet mastered even at age 5. All children produced the easier-to-produce low-frequency front-rounded-vowel variant, most at far greater frequency than in adult speech, implying that a child's output limitations can affect which variant the child targets for production. Modular theories, in which phonological plans reflect only the characteristics of adult input, fail to account for our results. Non-modular theories are implicated.

Uncommon timing variation in the speech of an Icelandic-speaking child with protracted phonological development.

The following paper presents an Icelandic-speaking child with protracted phonological development (PPD) over an intervention period (age 4;10 to 5;3) as a contribution to a special crosslinguistic issue describing individual profiles in PPD. Along with typical mismatch ("error") patterns, the child showed one pervasive and rare mismatch for Icelandic: compensatory lengthening of vowels when postvocalic consonant sequences reduced. Segment length is phonemic in Icelandic; thus, this pattern decreased her intelligibility considerably. A constraints-based nonlinear phonological framework served as a basis for analysis and intervention planning. Need addressed across the phonological hierarchy were: (1) accurate mapping between the timing tier (word structure level) and consonant and vowel tiers, through a focus on word-medial (WM) pre-aspirated stops; (2) onset complexity (word-initial (WI) /s/-clusters); and (3) a positional target, WI /f/. During intervention (17 sessions), she successfully produced training words for all targets. Monthly probes and a post-test at 5;3 revealed generalization to untrained words for pre-aspirated stops and labiodentals but not for /s/-clusters. Overall, compensatory vowel lengthening reduced substantially. The nonlinear analysis pointed specifically to the nature of the timing mismatches, supporting system-wide change.

When in doubt, glottal stop: A Mandarin-speaking three-year-old with protracted phonological development.

As part of a special issue on case profiles in protracted phonological development (PPD), we present a Mandarin-speaking three-year-old boy from Shanghai with severe PPD and no other developmental concerns. In comparison with typically developing (TD) children and a peer group from Shanghai with PPD, he had a very low Whole Word Match score (3.7% of words matched the adult targets exactly), reflecting severe constraints on word structure, consonants and diphthongs/triphthongs. His phonological output resembled that of younger children in its absence of fricatives, liquids and diphthongs/triphthongs alongside fairly high match for word length, tones and monophthongs, labials /p/ and /m/ and dorsal /k/. However, less expected was a pervasive glottal stop substitution in onset. The analysis describes his needs in detail but also strengths that could be exploited in phonological intervention.

Phonological variations in typically-developing Italian-speaking children aged 3;0-4;11.

Normative data on phonological acquisition of a language are a prerequisite for evaluating children's speech sound competences. To date, these data are not sufficiently available for Italian. This study, therefore, aimed to describe the phonological development of 183 typically developing monolingual Italian-speaking children aged 3;0-4;11 (four 6-months age bands). Participants were assessed through a picture naming task, and performances analysed in terms of number of phonological variations (Tokens), Types and percentage of occurrence of patterns, and number of infrequent variants (InfrVar) as a measure of stability in speech production. Two cut-off criteria to distinguish InfrVar from phonological patterns were applied. Results showed a gradual reduction of all measures with increasing age. Twenty-two patterns generally in line with previous Italian and cross-linguistic studies were observed, with only five patterns and two phonetic distortions occurring across all age groups. Eight patterns only emerged when applying the lower cut-off criterion, while further seven patterns only occurred with very low frequency or in isolated age groups. These findings highlight the influence of the selected cut-off criterion on the identification of patterns and raise the question of whether some patterns should rather be considered InfVar. Data on younger children are still needed to clarify whether low-frequency patterns are patterns of younger typically developing children that have almost resolved in the age groups assessed. At least half of the phonological variation Tokens fell into the category of InfrVar, indicating a need to pay more attention to this so far ignored measure.

Interdentals to the rescue: a German four-year-old with protracted phonological development.

This paper examines the phonology of a German four-year-old with asynchronous phonological development: age-level word structure and vowels, but a restricted consonantal inventory. Both expected and unexpected developmental patterns were evident. While the absence of dorsal non-continuants and most coronal and labiodental fricatives and affricates is not unexpected in four-year-olds with PPD, less expected was his mastery of more marked /l/ and /ʁ/ and the pervasive use of ungrooved interdental fricatives (or affricates) as substitutions. Ungrooved interdentals often replace grooved fricatives and affricates, but in his system, they also replaced stops in more marked prosodic positions (unstressed initial syllables and clusters) and labiodental /f/. His case profile demonstrates the autonomy of phonological tiers (levels) but also the restrictive interactions that occur when one tier dominates, in his case, word structure. A proposed treatment plan targets new feature combinations and consonant sequences in order to address the asynchrony.

Protracted phonological development of a Portuguese six-year-old from the perspective of nonlinear phonology.

As a contribution to a special issue with individual profiles in protracted phonological development (PPD), we present a European Portuguese-speaking six-year-old, "Vicente". By age six years, Portuguese-learning children have generally mastered most of the phonology. However, Vicente showed severe persisting PPD, which was negatively impacting his general socialisation. Although word length and stress often matched the adult targets as did many consonants and vowels, consonants were restricted in distribution and sequences. Consonant clusters showed a particularly high proportion of reduction. A constraints-based nonlinear phonological analysis led to a proposed intervention plan to address needs across the phonological hierarchy in the context of his greater need for enhanced socialisation: starting with the more attainable new word positions and sequences for consonants in his inventory, before addressing a major need for new word structure (clusters) and minor needs for segmental development (additional coronals).

Complexity and sequence constraints in a Granada Spanish-speaking four-year-old with protracted phonological development.

This article describes the phonology of a Granada Spanish-speaking 4-year-old boy with Protracted Phonological Development (PPD) from the perspective of constraint-based nonlinear phonology. Although he had acquired basic word structure and a near-complete repertoire of vowels and consonants, he had difficulties producing more complex word structures (multisyllabic words, clusters, diphthongs) and producing sequences of consonant manner and place features across vowels. The analysis outlines his strengths and needs in phonological development, and proposes an intervention plan to address constraints on complexity and sequences.

Complexity resolved: profile of a Slovenian child with protracted phonological development over an intervention period.

This paper describes the complex phonological patterns of one Slovenian-speaking girl with protracted phonological development who received phonological intervention. At 4;6, the child's word length, stress and vowels were age-level, but she showed reduced match levels (accuracy) for syllable structure and consonants. Unusual constraints on word position and sequences, particularly concerning fricatives and stops, resulted in many assimilations, reduplications and metatheses. Addressing these constraints in the first intervention period (to 4;9) led to higher overall accuracy and a transition from less typical to more typical mismatches ("errors"), e.g., sibilant grooving (stridency) and rhotic production as singletons and in clusters. The profile focuses on that initial pre- and post-treatment period, giving a brief overview of the follow-up intervention and outcomes and reflecting on implications for future research and clinical practice.11 The abstract is available in Slovenian language (see Supplementary material).

When codas trump onsets: an English-speaking child with atypical phonological development before and after intervention.

This case study presents an English-speaking preschooler with severely protracted phonological development (PPD) before and after two six-week blocks of intervention (36 sessions). Pre-treatment (3;8), he showed very low whole word, singleton consonant, vowel, and word shape matches. He had two major uncommon patterns: (1) higher accuracy for word-final consonants compared with word-initial (WI) and word-medial (WM); and (2) frequent substitution of onset consonants with glottals [h] or [ʔ]. Goals and treatment strategies were selected using a nonlinear phonological approach. Post-treatment, there was a notable decrease in frequency of glottal substitutions and concomitant increase in word shape, consonant, and vowel match. Pre- and post-treatment data are presented and discussed in terms of theoretical and clinical implications.

A Polish five-year-old with protracted phonological development.

This case study examines the phonology of a five-year-old Polish-speaking boy with protracted phonological development. A multi-tier analysis of his phonology revealed that word length, stress patterns, vowels and most consonants were largely compatible with the adult target while coronal consonants requiring fine control of tongue shape (fricatives, affricates, liquids) and most consonant clusters posed difficulty for the child in all word positions. Labial and dorsal features were well-established; in fact, [Labial] outcompeted other places of articulation in problematic sequences of both singletons and clusters. The case profile demonstrates asynchronous development of individual phonological elements and tiers. A proposed treatment plan exploits the child's strengths to address his needs and minimise the discrepancy between the tiers.

Consonants lost: a Swedish girl with protracted phonological development.

This paper addresses the phonology of a Swedish girl, aged 3 years 10 months, with extensive phonological difficulties that include an unusual phonological pattern. She had relatively well-developed phonological building blocks in terms of features, stress pattern and word length (number of syllables), but had extensive difficulties regarding syllable and word shapes, with frequent deletions of both segments and whole syllables. Word-initial position was dominated by non-continuant consonants, both voiced and voiceless, with extensive deletion. Word-medial position was dominated by voiceless obstruents, with extensive use of [j] in place of voiced consonants. Word-final position was similar to word-medial, but with more deletion than [j]. Non-initial stressed syllables resemble word-initial syllables. Consonant clusters mirrored singletons, i.e. with similar substitution patterns or deletions. We present a non-linear analysis of her speech production, and a plan for intervention targeting her special difficulties.

Individual profiles in protracted phonological development across languages: introduction to the special issue.

Although group studies provide necessary information about the range and frequency of phenomena in phonological development, individual profiles (case studies) can be used to describe entire phonological systems in detail. Profiles from different languages can highlight similarities and differences across languages that may be less obvious in group studies. The current issue presents profiles of children with protracted phonological development (PPD: speech sound disorders) from 16 languages (Akan, Kuwaiti Arabic, Bulgarian, Canadian English, Farsi, Canadian French, German, Greek, Icelandic, Japanese, Mandarin, Polish, European Portuguese, Slovenian, Granada Spanish, Swedish). Utilising a constraints-based nonlinear phonological framework, each profile describes a child's strengths and needs in word structure, segments, features and their interactions and suggests an intervention plan. Where available, follow-up data from after clinical intervention are included. This introductory paper provides the theoretical background for the papers and reflects on the findings, drawing out particular themes and implications for phonological and developmental theories and clinical intervention.

Idiosyncratic consonant clusters: a Farsi-speaking child with protracted phonological development.

This study presents a nonlinear phonological analysis of speech data from a Farsi-speaking child with protracted phonological development (aged 4;8) with very low accuracy on consonants. Results revealed some common phenomena (fricatives produced as stops; dorsals and non-anterior coronals produced as anterior coronals) and some uncommon phenomena (nasals produced as oral stops; voicing and devoicing of singleton obstruents in all word positions). These phenomena interacted in word-medial clusters to create an unusual sequence of two anterior-coronal or two bilabial stops, with C1 voiced and C2 voiceless, clusters which do not occur in the basic phonology of Farsi spoken by adults. We present a non-linear constraints-based analysis of the child's speech production and a plan for intervention targeting the child's special difficulties.