To be rigourous, Past tense in Diu Indo-Portuguese is expressed through verbal inflection, viz. through the use of various verbal suffixes:
e.g.
- pɛga 'to take' - pɛg-o 'took'
- bebe 'to drink' - bebe-w 'drank'
- subi 'to climb' - subi-w 'climbed'
For certain frequent verbs, past forms are suppletive:
e.g.
- vay 'to go' - foy 'went'
- traze 'to bring' - tros 'brought'
The forms above are, however, perfective. Imperfective aspect, on the other hand, is marked by a preverbal auxiliary te, which is verbal in nature and therefore acquires past tense inflection instead of the main verb.
For the purpose of this feature, what I am treating as a 'particle' is in fact the Past form of the perfective auxiliary: tiŋ (e.g. yo tiŋ kume 'I was eating'). No grammatical markers or lexical items can intervene between tiŋ and the main verb.
Source: Cardoso 2004-2008
Source: Cardoso 2009: 147