 The features under consideration here are linguistic units that reflect grammatical meanings such as tense, case, number, person, gender, or conceptual meanings such as evidentiality, habitual aspect and definiteness 

One key characteristic of these features is that they reflect variation across languages in their overtness, which became particularly important to GenSLA research.A feature of a word or phrase is said to be overt if there is surface evidence of its existence within that word or phrase.By contrast, a feature of a word or phrase is said to be covert if there is no surface evidence of its existence within that word or phrase.