The Interplay of Complexity, Genre, and Second Language Proficiency: A Commentary on "Complexity and Difficulty in Second Language Acquisition: A Theoretical and Methodological Overview".

A commentary on the article "Complexity and Difficulty in Second Language Acquisition: A Theoretical and Methodological Overview" is presented. It points out the lack of transparency of text analysis tools and argues that the proposed measures for language complexity, difficulty, development and proficiency conflict with the argument for appropriate complexity and nonlinear ways of complexity measures. It suggests elaboration of the moving-average type-token ratio for lexical diversity.