This word puts a country label on almost anything. It can sit in front of a person (a Russian teacher), an object (a Russian book), a dish (Russian soup), or a way of speaking (Russian grammar). It always begins with a capital R, even in the middle of a sentence, because it comes from the name of the country. It tells you where something is from or what it is connected to; it says nothing about what that thing is like.

Here the word is the person, not a description of one. You count it: one Russian, two Russians. Because it is a name-based word, the capital R stays. Two slightly different ideas share the one word. Most of the time it means someone from that country, whoever their family are. Sometimes, especially in writing about peoples and languages, it means someone of the Russian ethnic group, who may live in a different country. The sentence around it usually makes clear which one is meant.

When the word names the language, it stands alone. You do not put a in front of it and it has no plural, because a language is not something you count. It appears after verbs like speak, learn, study, read and teach, and after the preposition in: a letter in Russian. The capital R stays, as it does with English, Japanese and Taiwanese.