Introduction

Grammatical morphemes and functors, such as nominal and verbal inflections and determiners, are notoriously difficult for adult L2 acquisition across the board (passim the second language acquisition [SLA] literature). They have continuously drawn attention from researchers of all quarters. For example, L2 acquisition of English articles has been investigated under a range of theoretical approaches, from generative linguistic, to cognitive linguistic and to miscellaneous others, using a variety of designs and methods (e.g. Butler, 2002; Huebner, 1983; Liu & Gleason, 2002; Robertson, 2000; Thomas, 1989; White, 2003). Consequently, the literature has made available myriad explications regarding the nature and source of the morphological problem. However, conceptual and methodological problems render the existing proposals inadequate. Because the proposals are mostly based on studies that are non-longitudinal, that utilize pooled data, that treat grammatical morphemes as isolated, purely formal entities, and last but not least, that are target-centric (Larsen-Freeman, 2006), a number of key issues have remained poorly understood. One such issue is that of inter-learner variability. Learners from some L1 backgrounds apparently are, overall, more successful than those from other backgrounds in acquiring grammatical morphemes (Jarvis, 2002). Another paramount issue is intra-learner variability: Individual L2 learners display selectivity vis-à-vis grammatical morphemes such that they are able to fully acquire some but only partially acquire others (Franceschina, 2005). Additionally, the issue of persistent, variable use of certain grammatical morphemes (Lardiere, 1998; White, 2003) has not been adequately investigated.

This chapter seeks to contribute to the understanding of the last two issues, intra-learner variability and persistence. It brings longitudinal evidence to bear on, and provides an alternative to extant conceptions of, the morphological problem, in particular, as it relates to the English plural -s and articles. I will, heretofore, proceed as follows: first I will provide the theoretical background, highlighting the need to assume, in lieu of the existing perspectives, the perspective of linguistic relativism, more specifically, the thinking-for-speaking/writing hypothesis (Slobin, 1996a), in investigating the morphological difficulty.