Participants were 80 children (4;0-5;4) with phonologically-based speech sound disorders who participated in the Sound Start Study and completed the Polysyllable Preschool Test (Baker, 2013) three times. 
Polysyllable Preschool Test
Polysyllable errors were categorised using the Word-level Analysis of Polysyllables (WAP, Masso, 2016a) and the Framework of Polysyllable Maturity (Framework, Masso, 2016b), which represents five maturity levels (Levels A-E). 
Framework of Polysyllable Maturity