Distinguishing Usual and Unusual Phonological Processes in French-Speaking Children with Speech Sound Disorders

Dodd's (1995) classification system of speech sound disorder (SSD) makes a distinction between phonological delay and disorder, which is based on another distinction, namely of usual versus unusual phonological processes. Only children with phonological disorder display unusual processes. Dodd's (1995) classification system has been validated in English and other languages; however, it has not been validated in French. This study aims to distinguish usual and unusual processes in French-speaking children with SSD and, thus, identify children with phonological delay versus disorder.

Two existing datasets of children with SSD were analysed. The children (n = 37 in total), aged 3;11 to 7;7, were recruited from speech-language therapy clinics and administered a battery of tests which included a word naming task. The children's speech was phonetically transcribed and coded in terms of the presence of usual and unusual phonological processes.

The main usual processes (present in 50% or more of children) were cluster reduction and palatal fronting, with final consonant deletion, stopping, velar fronting and gliding being present in isolated children (i.e., 1 to 3 children). Only two processes, substitutions of /r/ by [l] and /v/ by [z], present in two children, were considered possible unusual processes. Other potential unusual processes were excluded because they have been observed in children with typical development, were marginally present in the data, or were present in the production of four-syllable words only.

The findings suggest that the separation between usual and unusual phonological processes in French is not easy to make, putting into question whether the diagnosis of phonological delay versus disorder can always be reliably made. Nevertheless, caution is advocated in the interpretation of the findings given the limited number of children with SSD tested and the use of multiple datasets.