'They become fluent within a year' says school head
Primary school children from English-speaking homes who go to Welsh-medium schools are less likely to be top performers in core subjects than pupils in English-medium schools.
But they are also less likely to underachieve, according to Welsh government figures.
They look at how 11-year-olds are doing in English, Maths, Science as well as first language Welsh in Welsh schools.
The performance of 25,000 pupils was compared.
The head of a Welsh medium primary school said young pupils became fluent within a year.
More than half of pupils at Ysgol Bro Cinmeirch in Denbighshire come from English-speaking homes but head Gwennol Ellis said children became confident to speak bilingually.