The research reported in this article examines Noun Phrase (NP) syntactic complexity in the writing of Spanish EFL
secondary school learners in Grades 7, 8, 11 and 12 in the International Corpus of Crosslinguistic Interlanguage. Two
methods were combined: a manual parsing of NPs and an automatic analysis of NP indices using the Tool for the
Automatic Analysis of Syntactic Sophistication and Complexity (TAASSC). Our results revealed that it
is in premodifying slots that syntactic complexity in NPs develops. We argue that two measures, (i) nouns and modifiers (a
syntactic complexity index) and (ii) determiner + multiple premodification + head (a NP type obtained as a result of a
corpus-driven analysis), can be used as indices of syntactic complexity in young Spanish EFL learner language development. Besides
offering a learner-language-driven taxonomy of NP syntactic complexity, the paper underscores the strength of using combined
methods in SLA research.