“lexical rule”here means“principle of free combination whose output is something of word size or smaller,”and“in
thelexicon”means not“stored in longter m me mory”but rather“involving principles thatbuild things of wordsize or
smaller.”That is,“lexical”in these terms really refers to thegrammaticalnotion of“word,”not to the notion of the
lexicon as stored information. Accordingly, I will stop using the term “lexical rules” in reference to productive
morphology.^77
6.2.2 Semiproductive morphology
Thesituationis quitedifferentwith semiproductivemorphology, wherethere are only partialregularities. A typical case
is the irregular forms of the English past tense. One canfind various generalizations, for example that many irregular
verbs for mtheirpasttenses bychangingthevowel,and thatirregularityisconfinedtomonosyllabicverbs(plus bi- and
trisyllabic verbs that begin with the quasi-prefixesa-, be-, for-,over-, andunder-). But even among verbs that are
phonologicallyvery similar,onecannotpredictexactlywhat thevowelchanges to: comparering-rang, wring-wrung, spring-
sprang, sting-stung, drink—drank, swing-swung, plus cases that are variable such asshrink-shrank/shrunk, stink-stank/stunk.
In addition, this class is interspersed with homophonous regular cases, such ashang-hangedandring-ringed(‘put a ring
around’) as well as the even more irregularbring-brought.Thusa“lexical rule”of this sort does not apply across the
board. Rather,givena ste mfor mthattherule potentiallyapplies to, one must know whether theruleactuallyappliesto
it.
When a word lacks a specified irregular inflectional form, the inflectional paradig m must still be co mpleted. For
instance, a verb must have a past tense form. So if thereis no irregular form, the regular combinatorial process jumps
in as a default. Derivationalmorphology, on the other hand, does not demand a regular pattern that serves as default,
so a semiproductive process can just leave gaps. Consider for example a class of English denominal verbs formed by
zero-affixation,such asbutter (the bread), water (theflowers), paint (the wall), roof (the house). These exhibita clear regularity, in
that they all mean
158 ARCHITECTURAL FOUNDATIONS
(^77) If there is an architectural distinction between phrasal syntax and morphosyntax, as suggested in section 5.6, productive affixes are treated by the latter. But this does not
mean that morphosyntax“takes place before”phrasal syntax, as in the“lexicalist”theories mentioned above. Rather, in accordance with the parallel architecture,
morphosyntaxgeneratesstructures in parallel with phrasal syntax, and thetwosubcomponentsinterfacewitheachother via theshared unit“grammatical word”and shared
features of inflectional morphology such as case and agreement features.