"It seems he speaks Russian."
Translation:Кажется, он говорит по-русски.
Yeh pretty much. быстро already means quickly so that wouldn't work. you can say побыстрее with means "a bit faster" Note the ER ending in russian which is typicall EE and the particle по
you could also say по-быстрому (note the dative ending here) but that is more colloquial way of saying "In a quick manner" давай по-быстрому (hurry up and do it quick)