Modern Persian verb stems revisited.

• Author: Henderson, Michael M.T.

1. More than a decade and a half ago I described the verb morphology of modern Persian as a six-slot string of constituents, each slot rewritten as a pair of features or as a phonological matrix(1). I The second section of that article listed the five large classes of verb stems, divided according to the differences between the present and

   (1) invariants, such as mandan `stay' xordan `eat'

   (23 verbs(2))

   (2) consonantal alternations, such as bastan/band(3)

   `tie' (70 verbs)

   (3) vocalic alternations, such as burdan/bar `carry'

   (15 verbs)

   (4) augmentative stems, in which the past stem is one

   or two segments longer than the present stem,

   such as danistan/dan `know' or nihuftan/nih

   `wear' (18 verbs, plus the productive i-augment

   class)

   (5) exceptional or suppletive verbs in which no responsible

   suggestion can be made that the alternations

   are rule-governed, such as bu/bas/ast

   `be' and dadan/bin `see' (18 verbs).

   Other members of class (5) may share one or more alternations with members of another class, such as zududan/zida `rub off', which shares a process with asudan/asa `rest' but has another, unique vowel alternation earlier in the stem.

   A linguist writing rules to describe linguistic phenomena such as these is trying to account for the knowledge that native speakers of the language have in their minds, and to do so in a manner which is consistent with a plausible view of a child's ability to acquire language. It is a plausible assumption, for instance, that confronted with a reasonably large set of examples of a particular phenomenon, a child will construct a rule which can be applied to as-yet-unheard forms. We know that this happens, because we have examples of children's overgeneralizations: English speaking children apply the regular past tense formation rule (add -d, devoiced to t after voiceless consonants, and insert [unknown character] first if the verb stem ends in t or d) to verbs which have irregular pasts: the English-speaking world is full of children producing forms like goed, comed, and sended. Effors like this tell us that our rules are in fact descriptive of rule-governed behavior. But we also write rules, such as the ten I listed in "MPVM," which look just like the kinds of rules a child might construct to account for a large body of data, but which in fact account for only one or two forms. These rules are just like the kind we could write to account for the many strong, verb alternations of English which have remained in the language, such as [unknown character] [left arrow] ey for the come/lcame alternation. It looks like a rule, and it could be written with distinctive features, but a rule is commonly accepted to mean "a description of a regularly occurring phenomenon." Just as it takes at least three aligned trees to make a row, it certainly takes more than one or even two examples to be a rule-governed...