The day has been observed throughout the world since 2000 as an initiative by Bangladesh. The idea was approved at the 1999 UNESCO General Conference as part of efforts to preserve the differences in cultures and languages that foster tolerance and respect for others.
UNESCO warns that linguistic diversity is increasingly threatened as more languages disappear.
Globally, 40 percent of the population does not have access to an education in a language they speak or understand, according to UNESCO.
The organization says multilingual and multicultural societies exist through their languages which transmit and preserve traditional knowledge and cultures in a sustainable way.
The theme of this year's celebration is “Using technology for multilingual learning: Challenges and opportunities.”
The aim is to discuss the potential role of technology to advance multilingual education and support the development of quality teaching and learning for all.
UNESCO Director-General Audrey Azoulay said in a message ahead of International Mother Language Day that technology can provide new tools for protecting linguistic diversity.
"Such tools, for example, facilitating their spread and analysis, allow us to record and preserve languages which sometimes exist only in oral form," she added.
Polish projects for International Mother Language Day included efforts to promote the correct usage of the Polish language and a list of the 100 most common mistakes made by Polish speakers, state news agency PAP reported.
The Polish Prime Minister's Office said in a tweet that "in the Polish alphabet you can find letters that are not found in any other, like: ą, ł, ś, ż."
It added that "Polish can be difficult to pronounce, but Poles love tongue twisters such as chrząszcz brzmi w trzcinie, which means 'a beetle buzzes in the reed.'"
(gs)