"Despite all our efforts, we failed to make our investments a focus of attraction for the people," said a joint statement by eight entrepreneurs read out at a news conference by one of the owners, Suleyman Yilmaz.
Turkey allowed private institutions to teach the language of the sizeable Kurdish minority in 2002 as part of reforms aimed at boosting its bid to join the European Union.
Since then, seven language centres had opened, mostly in the predominantly Kurdish southeast, and one was in the process of completing bureaucratic procedures before opening.
So far, 2027 people had enrolled in the courses, and 1056 of them had completed the programme.
Owners of the centres complained they faced bureaucratic hurdles and that the government failed to offer support.
The schools said they were not
supported by the government
They also realised that "nowhere in the world have a people learned their mother tongue by paying money," Yilmaz said.
Moreover, he said, "the Kurdish people already know the language that we want to teach them and what they want is ... to be educated" in that language in public schools and universities.
Public education campaign
The language centre owners would now support a campaign by the Kurds to use their mother tongue in public education, he said.
Under EU pressure, Turkey also launched Kurdish-language broadcasts on public radio and television in 2004.
Although the language programmes were welcomed as a breakthrough in a country where speaking Kurdish was banned less than 15 years ago, they failed to attract a considerable audience because of poor quality.
The reforms, however, helped Turkey win approval to start
accession talks with the EU on 3 October.
Kurdish demands for broader freedoms come at a time when the Kurdistan Workers' Party, blacklisted as a terror group by the EU and the United States, has stepped up violence in the southeast after calling a five-year unilateral truce in June 2004 on grounds that Ankara's reforms were inadequate.