A new study has suggested that children as young as six gain proficiency that is equivalent to adults in identifying verbs and their past tenses.
In the study, conducted by psychologists at the University of Liverpool's Child Language Study Centre, children aged between six and nine were given sentences containing made-up verbs such as 'the duck likes to spling.'
They were then asked to judge the acceptability of possible past tense forms.
The study focused on the process the children used to come to their conclusions rather than whether their answers were right or wrong.
The results showed that the children's judgements followed a virtually identical pattern to those of linguistics students who took part in a similar study at the University of California, Los Angeles, in the US.
University of Liverpool psychologist, Ben Ambridge, said: "Previous studies have concentrated on getting children to produce past tense forms for made-up words. This study is unique in that the children were asked to judge the acceptability of different forms that we gave them."
"One of the main questions raised when looking at children's ability to pick up their native language is whether abstract symbolic rules or the use of memory and comparison affect how a child attributes past tenses to words.
"The study was designed to investigate whether we coin novel past-tense forms like 'emailed' by applying the default rule of adding 'ed' to the present-tense form or by making an analogy with similar-sounding words stored in the memory, for example in the way we know to form 'sailed' from 'sail' by linking it to like-sounding words such as 'tail' or 'fail'.
"The study found evidence for the latter, supporting the view that we solve problems by making analogies with similar events stored in our memory rather than by applying abstract mental rules.
"Grammaticality judgements are generally used by adult linguists so it's impressive that children have been able to make them. They can't tell you how they do it, but even six-year-olds know when a made-up word just doesn't sound right," he added.