Zero-derivation
Further evidence that derived words are not necessarily found in the lexicon comes from first language acquisition. While English-speaking adults typically have production vocabularies of 20,000 to 50,000 words, children’s vocabularies are much smaller, ranging from about 50–600 words at age 2 to about 14,000 at age 6. To make up for this, children frequently coin new words (Clark 1995: 393, 399–401). One way children do this is to use zero-derivation, or conversion, a productive derivational process in English. Zero-derivation changes the lexical category of a word without changing its phonological shape. The following are all examples of novel verbs formed by 2- to 5-year-olds by zero- derivation. These examples are taken from Clark (1995: 402); the children’s ages are given in the format years;months:
(10) a. SC (2;4, as his mother prepared to brush his hair): Don’t hair me.
b. JA (2;6, seated in a rocking chair): Rocker me, mommy.
c. SC (2;7, hitting baby sister with toy broom): I broomed her.
d. SC (2;9, playing with toy lawnmower): I’m lawning.
e. DM (3;0, pretending to be Superman): I’m supermanning.
f. FR (3;3, of a doll that disappeared): I guess she magicked.
g. KA (4;0, pretending to be a doctor fixing a broken arm): We’re gonna cast that.
h. RT (4;0): Is Anna going to babysitter me?
i. CE (4;11): We already decorationed our tree.
j. KA (5;0): Will you chocolate my milk?
The fact that children, as well as adults, spontaneously create verbs like to lawn or to broom that they have never heard before tells us that there is more to morphology than the lexicon – there is also a generative component. Furthermore, the fact that the verbs in (10) were uttered once does not imply that they were automatically inserted into the speaker’s lexicon, as we would be able to show if later on we asked the same children to describe similar situations and it turned out that they did not use the nonce forms in (10).
We must mention directionality of derivation here. How do we know that a verb is derived from a noun or vice versa? If it is not obvious, we must research the answer in a good dictionary, one that contains etymologies.
It may happen over time that a word formed by zero-derivation or any other productive derivational process becomes lexicalized. So it is with the English verbs chair, leaf, ship, table, and weather. Another example of a verb that was originally derived via zero-derivation but is now listed in the lexicon is mail. In this case, we know that the noun came first because it was borrowed from the French male (Modern French malle) ‘bag, trunk’, referring to the receptacle in which letters were carried. Evidence that the verb is now stored in the lexicon comes from its frequency, as well as from the fact that its existence blocks the coining of potential but non-occurring derived forms, such as *mailbox ‘to put in a mailbox in order to send to someone’ (e.g., *I’m going to mailbox this parcel).
