The verh "budan/" is very productive in today"s modern Persian, having a
diverse behavior, semantically, morphologically and syntactically.
Morphologically speaking, the verb inflects two ways. It either appears as
"/hast-am/, /hast-i/, /hast-0/, /hast-im/, /hast-id/, and /hast-and/"or as"/
-(?)am/, /-(,?)i/ , /-(?)(a)st-0/, / -(?)im/, /-(?)id/, and /-(?)and/". The first set
comprising the root "hast-" plus the suffixes (I-am/, /-i/, /-ast-o/,/-im/, /-id/,
and /-and/) can occur in the sentance treely, so it is referred to as the "free"
forms. The second set, referred to as "bound" forms, lacks the root "hast-",
and acts as bound morphemes.
The verb "budanf is a polysemic onc, too, which functions both as a main
verb and as an auxiliary. As a main verb "/budan/" can either be a copula,
having no independent meaning, or as a content verb, synonymous to "to
exist".
As an auxiliary, the verb "/budan/" is added to the past participle of the
main verbs, to make the Persian present perfect.
"/budan/" as a content verb and as a copula differ syntactically in that the
former (meaning "to exist "), as an intransitive verb requiring only the
nominative noun phrase, is monovalent, while the latter, which links at least
the two arguments of subject and complement, is bivalent.
"jbudrenj" as a content verb has always got the phonetic manifestation of
the "free" forms. As a linking verb, all paradigms, except the third person
singular, may appear in both "free" and the "bound" forms. The third person
singular, however, appears as the "bound" form "/-(?)(a)st/". if it directly
occurs after the "complement". other wise it appears as "/hrest/".
As an auxiliary, the verb always appears in "bound" forms.