The Foundation Phase is a vital part of developing young children's skills in speaking, reading and writing in Welsh.
We have found that the rate at which children acquire Welsh language skills is affected by whether or not children are learning alongside others who share similar backgrounds in home language.
Our report shows that in classes with mixed linguistic backgrounds, children from non-Welsh speaking homes sometimes progress too slowly and the progress of pupils from Welsh-speaking homes can be hindered.
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Dull and damp for much of Wales as we start the day, with drier and brighter weather on the way this afternoon.
The heaviest of the rain will ease overnight. Remaining mild but breezy around coastal areas.
Every time you give blood, you save a life. And for 70 years, more than 10 million units of blood have been donated in Wales.