(By Hedvig Skirgård): "This feature covers all tenses (present, past, and future) 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 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, i.e. dedicated, productive and obligatory marking.
There are instances where TAM can be expressed by a combination of an affix and auxiliary or particle. For example, some grammarians state that tense is expressed by a certain form on the verbal root and an auxiliary. If this is a productive and obligatory way of expressing tense then such a construction triggers 1 for both this feature (GB121) and the features on bound tense marking (GB082/GB083/GB084). If not all parts of the discontinuous marking are necessary for expressing a tense, then only consider the marking that is obligatory.