Applied linguists have developed complex theories of the ability to communicate in a second language (L2). However, the perspectives on L2 communication ability of speakers who are not trained language professionals have been incorporated neither into theories of communication ability nor in the criteria for assessing performance on…

In the rating scales of major international language tests, as well as in automated evaluation systems (e.g. e-rater), a positive relationship is often claimed between lexical diversity, holistic quality of written or spoken discourses, and language proficiency of candidates. This article reports a "posteriori" validation study that analysed a…