While mother-tongue-based education is essential to the full development of individuals and to the transmission of linguistic heritage, 40% of the world's students do not have access to education in the language they speak or understand best. Such a situation severely undermines learning, cultural expression and the building of social relations, and significantly weakens the linguistic heritage of humanity.

It is therefore crucial that this language issue be taken into account in the necessary exercise of transforming education, which UNESCO was supporting throughout 2022, culminating in the Transforming Education Summit, convened last September by the Secretary-General of the United Nations, António Guterres.

This imperative first requires a better collection of data, which will make it possible to carry out specific and customized actions. Above all, however, it requires a more general awareness of the irreplaceable but fragile value of the world's linguistic and cultural diversity.

Each of the more than 7,000 languages spoken by humanity carries within it a unique view of the world, of things and of beings, a way of thinking and feeling – so much so that each disappearance of a language constitutes an irretrievable loss. In this context, the International Decade of Indigenous Languages (2022–2032), for which UNESCO is the leading agency, is an important opportunity for the international community to mobilize in order to safeguard a major part of the world's cultural diversity.

This is also the aim of this International Day: celebrating these ways of expressing the world in its multiplicity, committing to the preservation of the diversity of languages as a common heritage, and working for quality education – in mother tongues – for all.