An investigation of the speech sound and phonological development of monolingual Italian children aged 1;6-4;11

Obtaining data on the typical speech sound and phonological acquisition of a language is fundamental for a detailed description of the language-specific development, and as a baseline for the identification of SSD in children of that population. To date, normative data on Italian are not sufficiently available. This study, therefore, aimed to describe the speech sound and phonological development of 213 typically developing monolingual Italian children aged 1;6–4;11, across two cohorts (i.e. primary data on 3;0-4;11, and secondary data on 1;6-3;0). Participants in the two cohorts were assessed through two different naming tasks. Accuracy was calculated in terms of PCC and PVC; consonants and vowels inventories were drawn; geminates and two types of consonant clusters were also investigated. Phone production was investigated by two means: inventories were derived from a picture naming and a phone imitation task for children in Cohort 1. The 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 were calculated. Two cut-off criteria to distinguish InfrVar from phonological patterns were applied.
Overall results showed a gradual reduction of all measures with increasing age, demonstrating developmental progression. Replicating earlier data, the development of most Italian speech components was completed by the age of 4;11. Further studies on older children, particularly focussing on phonological patterns, are still needed. Unexpectedly, children did not show earlier production of consonants when these were imitated in isolation, thus raising questions on the appropriateness of the task for Italian. Even though clusters development was not investigated in enough detail, the analysis suggested the need for a more in-depth investigation, specifically with respect to the differences between development of tautosyllabic and heterosyllabic clusters, which have so far only been investigated as one group, as well as the observed phonological patterns affecting each type. Detailed data on typical phonological patterns and their age of overcoming are also presented. The application of two different cut-off criteria highlighted the significant influence of the selected criterion on which type of patterns might be considered developmental, and raises the issue of possible under-identification of SSD. InfrVar as a new measure was introduced for monolingual children; its diagnostic value needs to be further investigated. Finally, the influence of language-specific features and of regional variations children were exposed to was hypothesised in relation to a few findings across accuracy measures and phonological patterns found.