The bill which was adopted by the Sejm on April 26 and by the Senate on May 8, would have seen Silesian become Poland’s second legitimate regional language next to Kashubian.

It would have also opened the way to introducing the language into school language classes and onto notice boards in towns where over 20% of the inhabitants speak Silesian.

But posting on the X platform on Wednesday, the President’s Office wrote: “President Andrzej Duda refused to sign an amendment to the Act on National and Ethnic Minorities and the Regional Language into law on May 29, and sent it to the Sejm, the lower house of parliament, for reconsideration.”

It added that while making the decision, the president decided that the condition resulting from the act "enabling the Silesian ethnolect to obtain the status of a regional language" had not been met.

The office went on to quote the opinions of experts who believe that Silesian is a dialect of the Polish language.

Sejm speaker Szymon Hołownia responded on social media saying: “Diversity is Poland's strength, and not a threat to the country. I am sorry that you do not understand this, Mr President.”

He included a photo of the document signed by Duda.

The bill was initially submitted on January 25, 2024 by KO MPs from the main governing grouping led by Prime Minister Donald Tusk, as one of his 100 pledges made before the October 2023 General Election.

This was the eighth parliamentary attempt to recognise Silesian as a regional language or Silesians as an ethnic minority.

During the 2021 census, 596,224 people declared Silesian nationality, with 467,145 confirming they spoke Silesian at home.

The bill will now go back to the Sejm which can reject the president's veto with a three-fifths majority.