The initiative to celebrate Latvian as the sole official language of the country was proposed by president Egils Levits. The date goes back to October 15, 1998, when Latvian was confirmed as the official state language in the Constitution.
The State Language Center posted a congratulatory message on Twitter, reading "Language is my essence, my roots and my culture. I think in Latvian, speak Latvian and live in Latvian. I am proud to live in a country where I can freely express myself in my own language. Language is a treasure to be taken care of. If we don't take care of our language, nobody else will."
Justice Ministry also joined the congratulations.
ℹ️ Stiprinot valsts valodas nozīmi, šogad pirmo reizi, 15. oktobrī, oficiāli tiek atzīmēta Valsts valodas diena.— Tieslietu ministrija (@Tieslietas) October 15, 2021
🎉 Sveicam Valsts valodas dienā! 🎉 pic.twitter.com/q3U8ERReTo
So far, a celebration of the same name was marked May 13, though it has never involved major festivities.