What’s your first language ? My first language is Russian, even though I live in Kazakhstan. I speak Russian because, as you know, historically my country was part of The Union of Soviet Socialist Republics (USSR), commonly known as the Soviet Union. So the population mainly spoke Russian. I admit that to be maybe just an excuse, and to be honest, I am ashamed not to know my own mother tongue, which is Kazakh. For that reason, I have decided to study it. A period is needed after "Kazakhstan". You should not generally separate two complete sentences with a comma.

What’s your first language ? My first language is Russian, even though I live in Kazakhstan, I speak Russian because - if you know the history of my country - it was a part of The Union of Soviet Socialist Republics (USSR), commonly known as the Soviet Union. So mainly the population talked/spoke in Russian. I know, maybe it’s just an excuse, but to be honest I was ashamed not knowing my mother tongue language, which is Kazakh, so I decided to study it.