Editing Middle Persian (section)

=====Action noun suffixes=====
# ''-išn'' (''-šn<nowiki>'</nowiki>'') is by far the most productive suffix that forms action nouns and nouns with related meanings from the present stems of verbs: ''menīdan'' (''mynytn<nowiki>'</nowiki>'') 'to think' > ''men'''išn''''' (''mynšn<nowiki>'</nowiki>'') 'thinking, thought', ''xwardan'' (''OŠTENtn<nowiki>'</nowiki>'') 'to eat' > ''xwar'''išn''''' (''OŠTENšn<nowiki>'</nowiki>'') 'food'. The verbal noun in ''-isn'' (''-šn'') also functions in predicative position as a [[gerundive]], expressing that the action 'ought to be' performed: ''andar hamahlān ... hučašm bawišn'' (''<u>B</u>YN hmʾlʾn ... hwcšm bwšn'') 'among comrades ... one ought to be benevolent'.<ref name="Skjærvø 2007q">Skjærvø 2007: 65–66</ref><ref name="Расторгуева-13">Расторгуева & Молчанова 1981: 66</ref>
# ''-ag'' (''-k'') forms nouns (action nouns, but often with various concrete meanings) from verbs (both stems) and numerals: ''widardan'' (''wtltn<nowiki>'</nowiki>'') 'pass, cross' > ''widarag'' (''wtlg'') 'path, passage', ''čāštan'' (''cʾštn<nowiki>'</nowiki>'') 'teach' > ''čāšt'''ag''''' (''cʾštk'') 'teaching', ''haft'' (''hp̄t<nowiki>'</nowiki>'') 'seven' > ''haft'''ag''''' (''hp̄tk'') 'week'
This suffix is also thought to have had [[diminutive]] meaning and appears to have been added to already existing nouns with no change in meaning (''ǰām'' > ''ǰām'''ag''''' 'glass') or with an unpredictable change (''čašm'', sp. ''AYNE'', 'an eye' > ''čašm'''ag''''', sp. ''cšmk<nowiki>'</nowiki>'' 'a spring, well'). As such, it was a very productive and expanding suffix.<ref name="Расторгуева-14">Расторгуева & Молчанова 1981: 68–69</ref> It is identical to an adjective-forming suffix, and that it was its original function; on that, see the next section.