Is children's speech development changing? Preliminary evidence from Australian English-speaking 3-year-olds.

Purpose: Around 9% of children have difficulty acquiring intelligible speech despite typical sensory, neuro-motor and cognitive function. Speech-language pathologists (SLPs) rely on descriptions of children's speech errors to identify speech sound disorder (SSD) and determine intervention targets and goals. Existing normative data, however, need re-evaluation to reflect changes in populations and the language learning environment. This research evaluates whether developmental phonological patterns widely accepted as describing typical acquisition predict speech errors in a recent sample of pre-school children.Method: In 2015, 99 neurotypical children aged 3;0-3;8 years;months were assessed using the Diagnostic Evaluation of Articulation and Phonology (DEAP). Their performance was compared to studies describing speech development by children of the same age for phone repertoire and phonological patterns.Result: There were differences for both measures. Phone repertoire differences were marginal, but changes in phonological pattern use were unexpected. Suppression of three developmental phonological patterns (stopping of fricatives, final consonant deletion and voicing contrasts) was delayed compared to previous norms. Atypical consonant cluster reduction, sometimes considered a marker for disorder, was observed in 10% of children.Conclusion: There were qualitative differences in the speech development of the 2015 cohort of children compared to previous developmental norms. Valid and current normative data are necessary for the accurate identification of children needing intervention. The differences we found reinforce the need for regular updating of assessment tools, as well as greater understanding of how children's language learning environments are changing and potentially influencing speech development.

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.

Phenology of tropical understory trees: patterns and correlates

Reproductive phenologies of plants are constrained by climate in highly seasonal regions. In contrast, plants growing in wet tropical forests are freed from many abiotic constraints, which in canopy tree communities lead to a rich diversity of phenological patterns within and among individuals, species and communities. However, basic descriptions of tropical phenological patterns and the processes that shape them are rare. Here, we document the individual-, population-, and landscape-level phenological patterns of two dominant families of understory woody plants important to avian frugivores, the Melastomataceae and Rubiaceae, along an elevational transect in Costa Rica. The 226 individual plants belonging to 35 species in this study, varied in the number of reproductive bouts/year, and the timing, duration, and synchrony of reproductive stages. This variation was not related to factors related to their interactions with mutualists and antagonists, nor did it appear to be constrained by phylogeny. Diverse phenological patterns among species led to relatively aseasonal patterns at the community and landscape level. Overall, evidence for biotic processes shaping temporal patterns of fruiting phenology was weak or absent. These findings reveal a number of unexplained patterns, and suggest that factors shaping phenology in relatively aseasonal forests operate in idiosyncratic ways at the species level.

En regiones con marcada estacionalidad, los patrones fenológicos de las plantas están limitados por el clima. Por el contrario, las plantas que crecen en bosques húmedos tropicales, no tienen tantas limitaciones abióticas y es por esto que el dosel presenta una diversidad muy rica en los patrones fenológicos de individuos, especies y comunidades. Sin embargo, es muy escasa la información sobre la descripción básica de los patrones fenológicos tropicales y de los procesos que los afectan. En este documento, presentamos los patrones fenológicos, a nivel de individuo, población y paisaje, a lo largo de un transecto altitudinal en Costa Rica, para dos familias dominantes de plantas leñosas (Melastomataceae y Rubiaceae) que son de gran importancia en la dieta de aves frugívoras. En este estudio, las plantas variaron en el número de brotes reproductivos por año, así como en el tiempo, duración y sincronización de la reproducción. Esta variación no estuvo relacionada con interacciones con mutualistas y antagonistas, ni aparentemente estuvo limitada por la filogenia. Los diversos patrones fenológicos de las especies fueron relativamente no estacionales a nivel de comunidad y paisaje. En conjunto, hubo poca evidencia de que los procesos abióticos hayan afectado los patrones fenológicos de fructificación. Estos resultados revelan una serie de patrones sin explicación aparente, y sugieren que los factores que determinan la fenología en los bosques relativamente no estacionales, funcionan de manera idiosincrática a nivel de especie.