Parameter setting in the acquisition of consonant clusters by phonologically delayed children.

The relationship between the acquisition of initial complex onset clusters, /s/-initial clusters, and non-initial clusters is much studied yet poorly understood. Pan and Snyder (2004), working within the Government Phonology (GP) framework, proposed that the production of the three types of consonant clusters requires the proper setting of three binary parameters [+/- Branching onset (BO), [+/-Branching rhyme (BR)] and [+/-Magic empty nucleus (MEN)]. Specifically, the production of onset clusters require [+BO], /s/-initial clusters require both [+BR] and [+MEN], and non-initial clusters require [+BR]. Two predictions follow: (1) The acquisition of /s/-initial clusters is independent of the acquisition of onset clusters, and (2) /s/-initial clusters should never be acquired prior to non-initial clusters, because the latter only require [+BR]. These predictions were borne out by data from twenty English-speaking children with phonological delay (mean age = 4;10). In support of prediction (1), seven children were able to produce onset clusters, but never produced /s/-initial clusters, and four children had the opposite pattern. Consistent with prediction (2), six children produced non-initial clusters but were unable to produce /s/-initial clusters. We conclude that a parametric approach is applicable to the acquisition of consonant clusters in children with phonological delay.