In Russian school number 22, in the Latvian capital Riga, Natalia Skestere is quietly breaking the law.
Legislation puts a language barrier between the teacher and students
Under legislation which came into force last September, 60% of lessons in the final three school years must be taught not in the students' native Russian but in Latvian, the state language.
Natalia's history lessons fall into that category. She is Russian; so are her pupils; but they must speak Latvian in their lessons. Russian is permitted only in tiny doses, for translation purposes.
She is teaching them about Greek democracy. And despite the law, almost the entire lesson is conducted in Russian.
"They speak good conversational Latvian," says the teacher. "But it's not good enough for complicated ideas like this. They just don't understand the Latvian textbook."
She says she hands out crib-sheets in Russian to help them, "but strictly speaking, they are illegal".
The educational reform is part of the Latvian government's strategy to ensure that the country's large Russian-speaking minority - about 40% of the population - learns the state language and integrates more fully.
During 50 years of Soviet rule, the Latvian language suffered, as Russian became the main official language. Having won their independence 14 years ago, Latvians are now striving to restore their national identity, and want to make sure that all citizens of the country speak Latvian first and foremost.
But the Russian minority feels its rights are being trampled on.
"Russian is a great language," says school number 22's director, Natalia Rogaleva. "But for the Russians living here it is gradually being squeezed out. Soon it will remain only a household language."
Russian students: Latvia insists on integration
She says her pupils lose out in two ways.
Their Russian suffers from interference from Latvian: they mix up vocabulary and grammar.
And they no longer learn the subjects taught in Latvian so well.
Lera, a 16-year-old student, agrees: "I think it would be better to give us extra Latvian language lessons, to develop the grammar and vocabulary, instead of trying to do it in other lessons. That just worsens our knowledge of physics, chemistry, history, and so on."
Last year, huge protests were held against the reform, but Latvian officials say they were organised by Moscow.
When I asked the history class at school 22 whether they had taken part, however, most of the children thrust up their hands with an enthusiastic cheer.
Reversing the trend
It is a fact that during the Soviet period hundreds of thousands of Russian settlers felt no incentive whatsoever to learn the local language.
Many of the incomers were retired military officers, managers, engineers and communist bureaucrats. They behaved as colonisers do everywhere, bringing their own culture and language with them and feeling little need to integrate.
Now the Latvian government is determined to restore the primacy of the Latvian language.
Some criticise it for lacking sensitivity, and giving the impression that this is "payback time" for the years of Soviet rule. But the government denies it has rushed in the reforms.
"The education reform is a good tool," says Latvian Foreign Minister Artis Pabriks.
"It provides an opportunity for children to know equally well the language of their family and the state language of the country. The Soviet system did not do this."
I put it to Natalia Rogaleva that something surely had to be done to improve the integration of the Russians in Latvia.
"Yes," she says, "they should stop calling Russians 'occupiers' and 'immigrants', and stop calling all the time for Russian schools to be closed."
It is a tricky problem for the government of independent Latvia to solve.
There are as many Russians, proportionally, in Latvia as there are French speakers in Belgium. They argue that, being such a large minority, they should have the right to education in their native language if the demand exists - which it certainly does.
The say that Russian should be an official language with equal rights, just as Swedish is in Finland (for just 6% of the population).
The Latvians argue that education must primarily be carried out in the state language - and that if Russians want to learn in Russian they should pay privately for it.
It is a tough message - and one which could end up alienating the Russians, rather than integrating them.