In 2002, the first year that the guidance was relaxed, five pupils sat Higher French at Castlemilk; since then, a further three pupils have sat Highers and a total of 13 have taken French at Intermediate 2.
Uptake at Standard grade has dropped dramatically - from 98 sitting the exam in 2001 (the last year it was compulsory) to between 14 and 19 pupils per year in subsequent years. At the same time, the school roll has dropped from 594 in 2001 to 550 this year.
Likewise, the modern languages department has gone from four to two staff members.
Castlemilk High - which with its denominational neighbour, St Margaret Mary's Secondary, is one of the first of the Scottish Executive's "schools of ambition" - offers a snapshot of what is happening across Scotland.
Curricular flexibility and the notion of "entitlement" in modern languages have taken root and headteachers have chosen to give pupils greater freedom in the choice of non-core subjects.
Brian McAlinden, the school's headteacher, believes that greater choice benefits pupils. "I am happy that we have offered modern languages as a choice. They are no longer compulsory and this percentage of children (15-16 per cent of the year group) obviously see it as an important choice and want to do it.
"There must have been a group of pupils before 2001, when it was compulsory, who were able and gifted in modern languages but chose not to do them beyond Standard grade."
Mr McAlinden thought there were several factors at play. In the past, pupils did not take modern languages beyond S4 because they didn't have such a wide range of subjects to choose from. "There were children who could have done modern languages at Higher but who were switched off," he said. "They were sitting in a class in S3 and S4 who, by and large, didn't find it to be a really rewarding experience."
His modern language teachers are more guarded over whether the policy change is the right direction, he believes. "I think our principal teacher does not want to be the PT in Scotland who says that, by making modern languages non-compulsory, you get people who are more committed and staying with the subject later on.
"But I can maybe make the claim that these 15-16 per cent of pupils have voted with their feet and do want to continue with modern languages."
Castlemilk pupils still do French in P6-7 and S1-S2. However, if Glasgow City Council goes ahead with plans to move Standard grade courses back a year the entitlement to modern languages could be cut by a year.
In 2001, when 98 Castlemilk High pupils sat the compulsory French Standard grade exam, the average grade of all candidates was 3.8 (between General and Foundation). In the four years since it has been voluntary, and class numbers have varied between 14 and 19, the average grades have been 3.14, 3.5, 4 and 3.4. So, in three out of four years, the average grade has gone up.
Nationally, the trend in modern language uptake reflects this pattern: the number of pupils sitting modern languages at Higher has declined from 8,418 in 2002 to 7,939, and at Standard grade from 57,392 to 49,282. But at Intermediate 1-2, the numbers have increased from 3,181 to 6,060.
It was an issue much to the fore last weekend at the annual conference in Stirling of the Scottish Association for Language Teaching. Tim Steward, the association's honorary president, said: "Teachers would always rather teach willing volunteers than those who have been press-ganged.
"On the other hand, I think the more important question we should be asking in a broader context is: 'What is the implication of that?' If we take a look at our colleagues in other European countries, they see languages as being so important that they make them compulsory, saying you can't afford to be monolingual if you are in France, Germany or Spain. That is the reality of job mobility in Europe."
Mr Steward added: "Why are we struggling with languages? As far as I am concerned, the key thing is motivation rather than ability. If we take a look at the performance of kids in other countries, we have to conclude that a proportion of Scotland's population are radically different from populations in France, Germany and Japan."