Children fluent in two languages learn better in noisy classrooms than pupils who speak just one, research suggests.
Bilingual and monolingual pupils at a Cambridge primary school were asked to "identify the bad animal' in a series of recorded statements.
When another voice interrupted the statements, the bilingual children coped best, the study found.
This shows "the importance of learning a second language early", said co-author Dr Roberto Filippi.
The "acquisition of two languages in early childhood provides a beneficial effect on cognitive development," said Dr Filippi, senior lecturer in psychology at Anglia Ruskin University.
Cow bites horse
Some 40 children, aged seven to 10, from Histon and Impington Junior School, took part in the research.
Of these, half spoke just English. The others spoke English plus another language, including Italian, Spanish, Dutch, Armenian, Bengali, Polish, Russian and Portuguese.
The mean age of both groups was 8.8 years and the parents of both groups had been educated to at least degree level, say the researchers.
The children were presented with images of two animals, one on either side of a computer screen, and asked to listen to recorded statements describing one animal doing "a bad action" to the other.
They were asked to identify which animal was doing the bad action.
The sentences ranged from simple, for example: "The cow is biting the horse," to more complex: "It is the horse that the cow is biting."
Three sets of tests were carried out, starting with the statements without interruptions.
The second set of tests introduced a voice talking about something irrelevant in English, in the third set the voice spoke in Greek, a language none of the children understood.
Both statements and interruptions were delivered by a mix of male and female speakers.
The bilingual children were more accurate in the face of interruptions in Greek, with 63% right answers, as opposed to 51% for the monolingual group.
The difference between the groups in the other tests was smaller.
The bilingual children also improved as they got older, overtaking the rest by aged nine, say the researchers, writing in the journal Bilingualism: Language and Cognition.
They suggest this may be due to "more years of experience using two languages" and filtering out one when they are using the other.
"The observation that the ability to control interference improves with age, but only within the bilingual group, is a remarkable finding," said Dr Filippi.
Primary schools "are remarkably noisy", he added, "therefore the ability to filter out auditory interference is particularly important."
A small study of pupils at a Cambridge primary school found children who spoke only English were more easily distracted by noise.