¿"FAMILIA NUMEROSA" EN INGLÉS?
When I first came to Spain, I was surprised by the idea of a "familia numerosa" because it is not a common concept in the UK. Families with more than three children are very unusual in the UK, so I think that no specific subsidies for these types of families have ever really been established.
For that reason, it is also quite difficult to translate. Using "numerous family" will probably just confuse people, so it is much better to say "large family".
Hope that helps!
Soy el director de Daniel Smith + Partners. Tengo más de 15 años de experiencia enseñando inglés a españoles.