The research showed that babies who heard words were better able to ' categorise' pictures than those who simply heard tones.
Almost 50 three-month-old boys and girls were shown a series of pictures of fish, accompanied by either words or beeps.
The babies were then shown pictures of a fish and one of a dinosaur side by side and the researchers measured how long they looked at each image.
Looking at the fish longer than the dinosaur demonstrated they had categorised the fish in their minds, the journal Child Development reports.
The researchers said the results were 'striking'. The babies in the word and tone groups saw exactly the same pictures for exactly the same amount of time, but only those in the word group looked at the fish for longer.
Researcher Susan Hespos, of Northwestern University in Illinois, said: 'For infants as young as three months of age, words exert a special influence that supports the ability to form a category.
'These findings offer the earliest evidence to date for a link between words and object categories.'
Co-author Sandra Waxman said: 'We suspect that human speech, and perhaps especially infant-directed speech, engenders in young infants a kind of attention to the surrounding objects that promotes categorisation.
'We proposed that over time, this general attentional effect would become more refined, as infants begin to cull individual words from fluent speech, to distinguish among individual words and kinds of words, and to map those words to meaning.'
The remarkable ability of the baby's brain doesn't end there. Previous research has concluded they can communicate remarkably complex thoughts at the age of 12 months.
In an experiment that has echoes of the Bruce Willis film Look Who's Talking, researchers in Germany showed that year-old boys and girls are capable of understanding adults' thoughts.
In the study carried out by the Max Planck Institute in 2008, the infants were able to work out if the scientists needed help in finding objects that had fallen on the floor.
Then, if necessary, they made sure they got help to track them down.
The finding contradicts other studies which have suggested that the ability to understand what others know and do not know develops around the second year of life.
Other research has found that newborn babies cry with regional 'accents' copied from their mothers.
The discovery suggested that babies eavesdrop on their parents' conversations while still in the womb and are picking up their accents.
Read more: http://www.dailymail.co.uk/news/article-1260502/Talk-baby-using-real-words---boosts-brain.html#ixzz4v0r9RPRS
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