Since Ure (1971) and Halliday (1985), different measures have been proposed in the research literature as a proxy for investigating lexicon advances. They are called lexical richness measures and are an important tool in assessing advance of the lexicon (Johansson, 2009). This article evaluates three lexical richness measures of progress in the…

Morphological variability and the source of these errors have been intensely debated in SLA. A recurrent finding is that postpuberty second language (L2) learners often omit or use the wrong affix for nominal and verbal inflections in oral production but less so in written tasks. According to the missing surface inflection hypothesis, L2 learners…

Constituent structure is considered to be the very foundation of linguistic competence and often considered to be innate, yet we show here that it is derivable from the domain-general processes of chunking and categorization. Using modern and diachronic corpus data, we show that the facts support a view of constituent structure as gradient (as…