Babies understand what their mothers say, even if mum speaks in a language their child has never heard before, new reserach suggests.

Scientists have found one-year-olds react in exactly same way to their mother's voice regardless of whether she is speaking in English or Greek, proving what mothers have always known - that babies pick up on tone of voice rather than the words.

The researchers, from Cardiff University's School of Psychology, observed babies as they watched their mothers perform actions with toys using the English words "whoops' and "there".

The mothers then repeated the process in Greek, using the same tone of voice. The babies reacted to both languages.

Lead researcher, Merideth Gattis said children respond to "tone" clues in their parent's speech from an early age, and what they say isn't as important how its said.

The researchers, who published their findings in the journal Cognitive Development, studied 84 babies aged 14 to 18 months.

- DAILY MAIL