Short answers, pulled from the story.
Russian is the only official language at the national level in Russia. Article 68 of the Constitution of Russia restricts federal official status to Russian, while permitting individual republics to establish their own official languages.
Tatar is the largest minority language in Russia, with over 4.28 million speakers recorded in the 2010 census. Chechen follows at around 1.35 million, Bashkir at approximately 1.15 million, and Chuvash at just over one million.
Several languages in Russia are near extinction, including Votic with just 8 native speakers, Ter Sami with 2, and Ket with 20 speakers as of 2019. Since 1994, six languages have gone fully extinct: Kerek, Aleut in Russia, Medny Aleut, Akkala Sami, Oroch, and Yugh.
A 2015 survey found that 70% of Russians could not speak a foreign language. Among those with foreign-language ability, nearly 30% reported some knowledge of English, making it by far the most widely studied foreign language in the country.
Dagestan recognizes 14 literary written languages as official, including Russian, Avar, Lezgian, Azerbaijani, Chechen, Kumyk, Lak, Nogai, and several others. The republic's constitution defines state languages as Russian and the languages of the peoples of Dagestan.
Russia's regionally official languages span several families: Turkic languages such as Tatar, Bashkir, Yakut, and Chuvash; Uralic languages including Udmurt, Komi-Zyrian, and Erzya; Northeast and Northwest Caucasian languages such as Chechen and Kabardian; Mongolic languages including Buryat and Kalmyk; and Indo-European languages including Ossetic and Ukrainian.