"At the upper secondary school level, where instruction is partially in Estonian, the language skills of teachers are better than in primary schools," director-general of the Language Inspectorate, Ilmar Tomusk, said.

"There has been an improvement since the transition to Estonian as a language of instruction started in 2007 at the upper secondary school level of otherwise Russian-language schools. In Tallinn and in Harju County, the situation is somewhat better, with about 130 school teachers' Estonian below B2 level," Mr Tomusk added.

The inspectorate looked into the language skills of teachers in the Estonian cities of Narva, Kohtla-Järve, Jõhvi and Sillamäe. According to Mr Tomusk, while nursery school teachers need B2-level Estonian, assistant teachers only need A2, which is the lowest language level required by the Language Act.

"In the cities of Ida-Viru County, language skills of about 450 nursery school teachers and 260 assistant teachers still don't meet requirements," he added. "In Tallinn and Harju County, there are another nearly 350 nursery school teachers and 80 assistant teachers [whose Estonian is below the required minimum]. Thus there are some 1,800 education professionals in total in Ida-Viru County, Tallinn and Harju County whose language skills don't meet requirements," Mr Tomusk pointed out.

Number of teachers with insufficient skills declining

Mr Tomusk also stated that the number of teachers across educational levels who do not have sufficient command of Estonian has been shrinking lately.

While a 2003 report of the Language Inspectorate of teachers' Estonian skills had Kohtla-Järve personnel at 258 out of 338, this number by 2018 had dropped to 146.

Another report with preliminary findings published in 2006 stated that 2,119 teachers at Russian schools out of a group of 2,315 across the country did not meet language requirements—that is a good 90% of the total number.

By 2018 the situation improved to the point where just over 600, or 19%, of a total of 3,200 teachers at Russian general education schools were found to have insufficient Estonian skills, most of them in Ida-Viru County and in the same group found to be lacking in the most recent report.

Thousands of teachers needed for full transition to Estonian

Mr Tomusk pointed out that for a transition to mainly Estonian-language instruction across the country, at least a couple of thousand additional teachers with proficient Estonian skills would be needed.

This doesn't just affect Estonian language lessons, but also maths, history, chemistry and plenty of other school subjects, Mr Tomusk said. In addition, nursery school teachers would have to raise their levels as well, otherwise there can be no talking about immersion schools, he added.

The issue will become less urgent over time, as Estonia's universities are no longer offering certification for teachers only working in Russian. Also, the average age of teachers at above 50 as well as some 25% of teachers approaching retirement age will contribute to the solution of the problem, Mr Tomusk finds, though this won't happen too soon.