Speech sound errors of Mandarin-speaking preschool children with co-occurring speech sound disorder and developmental language disorder.

This study examined the occurrence and types of speech sound errors in Mandarin-speaking children and compared those with co-occurring developmental language disorder (DLD) and speech sound disorders (SSDs) to those with SSD only and those with no DLD or SSD. The participants were 64 four-year-old Mandarin-speaking children, including 20 age-matched children with co-occurring SSD and LI (SSD + DLD), 20 with SSD only, and 24 with no DLD or SSD (typical development [TD]). Speech samples from a list of 20 pictures of common objects and animals were elicited in a picture-naming task. One speech-language therapist transcribed and analysed consonant production accuracy and coded speech errors into the types of substitution, omission, distortion, and addition and phonological processes into typical and atypical sound changes. The interrater reliability of consonant production analysis was checked by another experienced speech-language pathologist. Children with co-occurring SSD and DLD demonstrated the least accuracy of speech production among the three groups of children. Children with co-occurring SSD and DLD showed more frequent use of substitutions, omissions, typical sound changes (i.e. stopping of affricates, stopping of fricatives, deaspiration), and atypical sound changes (i.e. initial consonant deletion, fronting, affrication of stops) than children with SSD only, while no significant difference between the SSD and TD groups was observed in omission error types and atypical sound changes. These results suggest that the disorders in speech sound production in children with SSD and DLD may be associated with underlying phonological-linguistic processing.