Ukrainian is a Slavic language spoken by about 41 million people in Ukraine, Poland, Slovakia, Russia, and in enclaves around the world.
Only about three-quarters of Ukrainians are first-language speakers of Ukrainian.  Kiev is a little confusing to the novice Russian student, as the signs are half in Ukrainian and half in Russian.  Since the breakup of the Sovient Union, there has been a resurgence in the Ukrainian language.
There are millions of first-language Ukrainian speakers in Russia, Belarus, and the Central Asian republics.