Figures show 6,500 under-eights are being taught in illegally-high classes of 31 or more up from 4,280 last year.
The problem is heightened with a record 824,000 school children speaking English as their second language.
One in seven primary-age pupils speaks a foreign language as a first tongue, the Government statistics show.
In inner-London more than half 53.4 per cent have English as a second language. Many hail from eastern Europe.
Shadow Schools Minister Nick Gibb said: "It is clearly more difficult for teachers if children arrive at school unable to speak English
Figures show 6,500 under-eights are being taught in illegally-high classes of 31 or more up from 4,280 last year.
The problem is heightened with a record 824,000 school children speaking English as their second language.
One in seven primary-age pupils speaks a foreign language as a first tongue, the Government statistics show.
In inner-London more than half 53.4 per cent have English as a second language. Many hail from eastern Europe.
Shadow Schools Minister Nick Gibb said: "It is clearly more difficult for teachers if children arrive at school unable to speak English