A simple method of investigating the sub-units in which speech is perceived was proposed. The aural presentation of a story was abruptly stopped and followed by a retention interval task which was designed to displace from short-term memory its contents. It was argued that the recall, after the task, of the last word retained would be the final word to enter long-term memory and hence the terminal word of a sub-unit. The results showed that subjects' recall followed a common pattern which appeared to be syntactically determined.