Past tenses
The topic time of the verb of the sentence may coincide with the time of speech (present tense) or precede it (past tense). The languages of the world form two large groups with respect to whether or not they have such a grammatical distinction.1
Some languages mark remoteness distinctions within the perfect. Such distinctions include “today’s past” and “yesterday’s past” or earlier, and some languages can even distinguish two recent pasts and three distant pasts. These may include the very distant past or a mythological past.
To determine the parameter value for a language, the past tense should be considered only as it appears in independent main clauses.
Types:
NoPst: There is no grammatical distinction between past and non-past.
Pst: There is either but one grammatically distinct past tense or several ones that are differentiated by principles other than expressing the distance of the event in time.
2Pst: There are two grammatically distinct past tenses that express the distance of the event in time.
XPst: There are x grammatically distinct past tenses that express the distance of the event in time. (X should be replaced with the actual number of past tenses.)