Development of clausal and subclausal grammatical complexity and their relationship to overall length in second language writing over a year

The present study investigates the development of the overall length, clausal (coordination and subordination) and subclausal grammatical complexity of paragraphs written by second language learners, employing both general indices for these dimensions and fine-grained measures of nominal complexity included in automated text analysing tools of grammatical complexity, the L2SCA and the TAASSC. Adult learners of English with an intermediate level of proficiency (N＝17) wrote paragraphs on eight topics over a year. The results showed that : a) grammatical complexity developed in order from subordination through phrasal elaboration and overall length to coordination, b) learners made a sentence longer by adding more subordinate clauses in the initial phase and by lengthening a clause in the final phases of development, and c) nominal subtypes also showed diverse developmental speeds with commonalities in that modifying elements were initially and finally added onto nominals in general and the nominals in subject and direct object slots in particular, with their reductions in the middle phase. The paper concluded that, if general developmental trajectories from coordination through subordination to phrasal elaboration found in the literature were interpreted in terms of overall length rather than via the time of learning, the trajectories were robust.