Why does the production of some learners not grammaticalize

In this paper we follow two beginning learners of English, Andrea and Santo, over a period of 2 years as they develop means to structure the declarative utterances they produce in various production tasks, and then we look at the following problem: In the early stages of acquisition, both learners develop a common learner variety; during these stages, we see a picture of two learner varieties developing similar regularities determined by the minimal requirements of the tasks we examine. Andrea subsequently develops further morphosyntactic means to achieve greater cohesion in his discourse. But Santo does not. Although we can identify contexts where the grammaticalization of Andrea's production allows him to go beyond the initial constraints of his variety, it is much more difficult to ascertain why Santo, faced with the same constraints in the same contexts, does not follow this path. Some lines of investigation into this problem are then suggested. We take the view that there are a limited number of pragmatic, semantic, and phrasal (morphosyntactic) organizational principles at work in learner languages, and that their interaction determines the actual organization of a given learner variety. The kind of interaction, and hence the specific contribution of each princi-ple, may vary as a function of source language influence and of the proficiency level of the learner. Thus, the process of acquisition1 can be viewed as the change in the interaction of these principles over time, and grammaticalization as one direction this change may (but need not) take, where the learner comes to give relatively more weight to phrasal principles. In this paper we follow two beginners (Andrea and Santo, who share Italian as a source language and who acquired English in England) over a period of 2 years as they develop means to structure the declarative utterances they produce in narra-tives of personal experiences, interviews, and descriptions of future plans and in