1.- A city of federal importance has the status of both an inhabited city and a constituent federal subject. In Russia there are three federal cities: Saint Petersburg, an important port on the Baltic sea, Sevastopol annexed by the Russian Federation in 2014 and Moscow the capital of Russia. We have to bear in mind that every federal subject in Russia ha its own head, a parliament and its own court.
2.- Only Russian is recognized as a national official language but the article 68 of the Russian contitution only allows the various republics of Russia to establish official (state) languages other than Russian. Some of these languages are: Abaza, Adyghe, Althai, Bashkir, Buryat Chechen, Chuvash, Crimean Tatar, Erzya, Ingush, Kabardian, Kalmyc, Karachay-Balkar, Khakas, khomi, Hill Mary, Meadow Mari, Moksha, Nogai, Ossetian, Tatar, Tuvan, Udmur, Ucranian, Yakut.
You can notice that Russia is a diverse country and if you l travel it is going to be a little bit hard to communicate if you only speak English. Learning some basic Russian helps to communicate and if you go far beyond Moscow a tourist guide will be necessary.
