Languages, regardless of level, vary in terms of sounds, structure of words and the way words are put together to make grammatical sentences. Yet despite these clear differences, there is an underlying uniformity to the systematic ways language is used. This is most clearly seen in our informal conversations, where we take short, two second turns speaking with very small gaps in-between. It is within these gaps that the EU-funded INTERACT project looked in order to better understand the interactional foundations for language. What they discovered is that these foundations are visible early in ontogeny, are independent of language or modality, and are universal across cultures. Significant insights During the course of the project, researchers made several significant findings. For example, they found that in an informal conversation, the gap between turns speaking average only 200 milliseconds – often less. This is remarkable considering that it takes 600 milliseconds to prepare even a single word for speaking, and 1 500 to prepare the most basic of sentences. ‘What this means is that we beat the clock by predicting how the current speaker will complete the turn and already start to produce our own words as soon as we have enough information to do so,’ says INTERACT Project Coordinator Stephen Levinson. ‘At the same time, however, we need to keep listening, even as we prepare to speak, in order to check our prediction and to come in on time – multi-tasking that is cognitively intense.’ To understand the cognitive challenge of turn-taking, the project specifically focused on language development in children. ‘Pre-linguistic infants are reasonable quick to respond with simple vocalisations, but as they learn to understand and speak, their response times get quite slow – three to four times slower than adults – and do not pick up speed until later in childhood,’ explains Levinson. According to Levinson, in order to respond appropriately, children have to learn to recognise whether an incoming turn is, for example, a question or a request. ‘At a very early age, children become attuned to often very indirect cues,’ he says. Looking back to understand the future Based on its research, the INTERACT project determined that the timing in turn taking is more or less constant across languages and cultures. It is also the same in non-spoken sign languages. ‘The early development in infancy and the universal character of the system suggest that this may have been an early established platform in the origins of language,’ says Levinson. ‘Indeed, vocal turn-taking can be found across the primate order, and gestural, non-vocal turn-taking has very similar timing in the great apes.’ Project researchers also found that the existence of this interactional system can be seen in the contrast between such human cognitive syndromes as autism, where the system is impaired, and Down syndrome, where it is not (even though often times speech impediments are present). ‘Our research into better understanding the human interactive speech system not only has potential benefits for medical research, above all, it will be crucial to improving human-machine interaction,’ concludes Levinson.
INTERACT, conversation, language, speech, interaction