The relative ease with which children acquire language has produced much debate and theory, mirroring the similar quantity of debate and theory over how we evolved language. One theory of language evolution is that it began with gesture. A recent study looking at how deaf children learn sign language might perhaps be taken as partial support for this theory, and may also have wider implications for how children acquire language and how we can best support them.
The study, involving 31 deaf toddlers, looked at 89 specific signs understood and produced by the children. It was found that both younger (11-20 months) and older (21-30 months) toddlers understood and produced more signs that were iconic than signs that were less iconic. This benefit seemed to be greater for the older toddlers, supporting the idea that a certain amount of experience and/or cognitive development is needed to make the link between action and meaning.
Surprisingly, the benefits of iconicity did not seem to depend on how familiar, phonologically complex, or imageable the words were.
In contrast to spoken language, a high proportion of signs are iconic, that is, related to the concept being expressed (such as, bringing the hand to the mouth to indicate ‘eat’). Nevertheless, if iconicity is important in sign language, it is surely also important in spoken languages. This is supported by the role of gesture in speech.
The researchers suggest that iconic links between our perceptual-motor experience of the world and the form of a sign may provide an imitation-based mechanism that supports early sign acquisition, and that this might also apply to spoken language — with gestures, tone of voice, inflection, and facial expression helping make the link between words and their meanings less arbitrary.
This suggests that we can support children’s acquisition of language by providing and emphasizing such ‘scaffolding’.
 . The Road to Language Learning Is Iconic Evidence From British Sign Language. Psychological Science [Internet]. 2012 . Available from: http://pss.sagepub.com/content/early/2012/11/09/0956797612459763