deficits despite a half-size brain. Similarly, Lenneberg's (1967) discussion of Seckel Syndrome (“nanocephalic dwarfs”)
did not report massivelyimpaired vocabulary learning in these individuals with chimpanzeesized brains. This evidence
hints that the effortlessness of vocabulary acquisition is indeed a human cognitive adaptation. Though apes can learn
vocabulary, I suspect that this learning is qualitatively different, rather like children's learning of reading: a largely
effortful undertaking requiring much motivation and instruction, quite unlike children's spoken (and signed) word
learning, which is rapid and spontaneous.
Late second-language learners can be counted on to acquire substantial vocabulary, even when their grammar and
especiallypronunciationis far fromfluent.Inthefamous case of“Genie”(Curtiss 1977), vocabulary acquisition began
immediatelyupon her discovery, and her rate of vocabulary acquisition approximated that of young children. Yet after
years of training, her grammar remained exceedingly rudimentary. Parallel results obtained in a similar case are
reported in Curtiss (1994). These well-known facts suggest that the capacityfor an open vocabulary is independent of
that for grammatical elaboration.
At some point, then, the hominid line had to adapt to learning this vast number of symbols. As Donald (1991)
observes, the uniquely human ability to imitate—yet another important cognitive adaptation—obviously plays a role
herein theacquisition of thesounds of words. And given theimportance of pointing (bothby parents and children)in
early language acquisition, it is surely significant that apes do not appear to appreciate pointing in the way that human
infantsdo from beforeoneyear ofage(Povinellietal. 2000).Imitationand pointingarebothimportantpreadaptations
for the acquisition of an open vocabulary.
In turn, in order for there to be this vast number of symbols to learn, hominids had to be adapted to be able
occasionallytoinventnewsymbols, yet anotheradaptation. Itis notclear tome howmuchmetasymboliccapabilitythis
would require; the issue requires more investigation, perhaps by looking at the metasymbolic abilities of very young
children.
8.5 A generative system for single symbols: proto-phonology
As the class of symbols becomes larger, the perceptual problem arises of making all the utterances discriminable and
memorable.If thesymbols wereholistic vocalizationslike primate calls, evena thousand symbols wouldbe impossible
to keep distinct in perceptionand memory (Nowak et al. 1999). Modern language deals with this problem by building
words up combinatorially from a repertoire of a few dozen smaller meaningless speech sounds. Using concatenated
speech