One in four primaries says they will not be ready - or cannot guarantee they will be ready - to introduce language teaching when it becomes compulsory in 2011, a government-funded study has found.
Researchers at the National Foundation for Educational Research found that during the three years from 2006 to 2008 the number of primaries offering some language teaching to junior pupils had risen from 70 to 92 per cent.
But only 69 per cent were meeting the requirement to give all key stage 2 pupils language teaching during class time.
Schools that struggled said the issues were: finding time to deliver languages within a crowded curriculum; lack of staff expertise and confidence; and the impact on budget and staff training needs.
French was the language most commonly offered, and the most typical way of teaching languages was in a discrete 40-minute lesson once a week, the researchers found.
Therese Comfort, head of primary languages at CILT, the National Centre for Languages, said: "Although there is still much to be done, we are really encouraged by the amount of energy that primary schools across England are putting into creating language provision and making language learning a fun and valuable experience for children.
"We are delighted that more children than ever are learning languages and hope that they will carry their enthusiasm through into both secondary school and later life."
In December 2002, all primary schools were told that by 2010 they would be expected to offer languages to pupils from the age of seven, but at the time this was not intended to be compulsory because of lack of teacher expertise and a need to review the curriculum.
But when Lord Dearing recommended in his 2007 review of language provision that they should be compulsory in primaries, the Government agreed to make room in the curriculum.
Sir Jim Rose's primary curriculum review, which includes an investigation of language provision, is now entering its final stages and the new arrangement is expected to be introduced in 2011.
A two-year study of secondary language teaching found that its introduction in primaries had made little impact.
The study, by Cambridge University's Dr Michael Evans and Linda Fisher, found that while secondary teachers, heads of department and pupils all supported the principle of teaching languages to younger children, few felt that primaries affected what pupils experienced in their secondary years.
The academics reported: "In practice, the impact of the primary initiative on the secondary curriculum was weak, with languages departments still generally unclear as to how to meet the challenges of the Year 7 mixed- experience classes and ensure good progression on the language work done in the primary school."
The study also found that 75 per cent of teachers thought the changes at key stage 3, which include explicit learning objectives and an explicit focus on grammar, had improved language learning for their pupils.
But almost half (46 per cent) said making languages optional at KS4 had caused younger pupils to become disaffected.
Just one in four of the poorest teenagers take a modern foreign language at GCSE compared with four in 10 of those from richer backgrounds, according to the latest figures from the Department for Children, Schools and Families.