Persian verbs as a part of speech and therefore a morphological entity have, as a rule, internal structures both of derivational and inflectional types. The derivational structure of verbs in Persian is very limited with only five structural patterns, namely, simple, complex, compound, phrasal and a special pattern that is conjugated in the .3rd person singular only. Of these, the first two patterns are not productive; and since the remaining three are syntactic in nature, the derivation of verbs in Persian has acquired a syntactic nature. This has no doubt caused certain complications in Modern Persian.
The inflectional structure of verbs in Persian is, on the other hand, extremely complex; comprised of several patterns namely those of participle (one term) voice (two terms) infinitive (one term), tense (three terms: past, present and future) mood (three terms: indicative, subjunctive and imperative) aspect (four terms:
simple/continuous, perfective/ imperfective) and person plus number (six terms: three persons each singular or plural).
Since these patterns function together, at least in principle, it is difficult to describe them particularly as some may remain without exponents. To overcome this difficulty, it is essential to treat them
hierarchically. This approach shows that there are three derivational strata in the derivational structure of Persian verbs and seven inflectional ones. This will, no doubt, make the description of Persian verbs extremely simple.
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