A study showed that pupils in Holland spent even less time than Scottish children on learning a foreign language in primary but were way ahead in language development. "That makes the teacher's job easier," Professor Johnstone said.
Television programmes were not dubbed and children picked up English naturally.
In contrast, Scottish pupils faced no such foreign language environment and struggled with motivation. Similarly, students in Germany did not necessarily see themselves living in their homeland all their lives, whereas the tendency for Scots students was to stay put.
To counter that, students should spend more time in a more intensive way picking up language skills, possibly learning earlier in primary, Professor Johnstone suggested.
"I would have to say it does concern me that in some schools the amount of time from P6-S4 is a good bit less than 500 hours and 500 hours is not enough to deliver proficiency. There is a difference between proficiency and attainment," he said.
There was nothing in the Scottish Executive statement on languages to suggest study of a modern language was optional, Professor Johnstone observed.
Roy Cross, director of the British Council Scotland, forecast the steady demise of English as the all-powerful world language. Only a third of internet traffic was now in English, Mr Cross warned. He also appealed for an earlier start to languages.
Dorothy Senez, European Commission spokeswoman, said a study across Europe showed that English was the most commonly used language and 77 per cent of people questioned said it was their preferred foreign language. Just over half (56 per cent) felt they could hold a conversation in English. Yet 44 per cent of English people did not know any foreign language.