The present study comprises a phonetic analysis of the lateral phoneme /l/ in the first (L1) and second language (L2) of 10 late German–English bilinguals. The primary objective of the study was to compare the predictive power of dynamic systems theory with that of maturational constraints through a phonetic investigation of L1 attrition in the lateral phoneme /l/ of the late bilinguals.

The results revealed L1 attrition in the lateral phoneme /l/, as well as a high degree of interpersonal and intrapersonal variation. These patterns are discussed in relation to dynamic systems theory and maturational constraints. Moreover, the degree of permanency of L1 attrition is discussed in relation to methodological considerations in studies on L1 attrition. It is proposed that maturational constraints are insufficient in explaining the results and that bilingual language development can be more adequately explained through dynamic systems theory, which explicitly incorporates a multitude of predictor variables across the lifespan, in addition to age constraints.