Triggering a principle of phonemic acquisition.

This experimental clinical study evaluated different treatment manipulations of the principle of Laryngeal-Supralaryngeal Cyclicity as a follow-up to Gierut (1994b). Laryngeal-Supralaryngeal Cyclicity states that the acquisition of phonemic distinctions will occur as a bivalent cycle with laryngeal and supralaryngeal distinctions emerging in turn. In this study, children with seemingly static phonemic systems participated in a treatment programme that introduced sequentially new distinctions to the inventory. One child was presented with alternating laryngeal and supralaryngeal properties consistent with the principle, whereas the other child was exposed only to consecutive supralaryngeal distinctions. Results indicated that the latter treatment condition triggered greater phonemic expansion, as based on the longitudinal course of emergent phonemic distinctions for each child. These findings were comparable to those of the earlier investigation, and have implications for treatment efficacy and theories of language acquisition.