(By Hedvig Skirgård): "This feature covers all grammatical aspects (internal temporal constitution of events/actions/states) and aims to capture phonologically free elements that inflect (i.e. change form depending on person, number and other categories of the core arguments). These markers are often described as ‘auxiliary verbs’ in the literature, but they are also analyzed under other labels by some authors (such as STAMP morphemes (STAM = Subject-Tense-Aspect-Mood-Polarity) or inflecting pronouns). We are interested in grammatical marking, that is, dedicated, productive and obligatory marking.