I will admit that I was not totally happy with the system of using suffixes for the progressive and perfect forms of verbs. Since the prefix “ge-” is used for passive forms of the verb it seems logical to resume the system of using prefixes for progressive and perfect too.
What was not made clear in previous posts was that progressive and perfect constructions can also be made using auxiliary verbs, as in English and many other languages.
For progressive/ continuous constrictions the auxiliary “bi” (to be) can be used, although I see no reason why “du” (to do) might not be used too. For perfect constructions the auxiliary verb “av” (to have) is used. A case may be made for also having a dedicated perfect marker such as “dun” or “did” too. This would avoid inelegant “have had” or “had had” constructions.
The prefixes are “is-” for progressive/ continuous and “va-” for perfect, although this latter may change if there is a better suggestion. “ge-” is used for passive constructions. The prefixes are more useful for use as gerunds or adjectives. I suspect most adjectives will use “is-” and “ge-” rather than “va-” but there may be exceptions. Auxiliaries and prefixes may be used together, which is likely with constructions that combine the perfect and progressive. For example, “past progressive perfect” would be “wen av is-VERB” or “wen dun is-VERB”.