Listen carefully to a spoken conversation and you’ll notice that the speakers use a lot of little quasi-words—mm-hmm, um, huh ...

“With huh? you say not just ‘I didn’t understand ... “I don’t think we would have complex language if it were not for these simple words.” To make artificial intelligence ...

When they did, they observed that interjections—that is, short utterances of just a word or two that are not part of a larger sentence—were ubiquitous in everyday speech. “One in every seven ...