Terve Cleiber The difference is not huge but yleensä is an adverb related to yleinen 'common, typical', and tavallisesti is the adverbial form of tavallinen 'usual, normal, ordinary', i.e. typically vs usually. There is a lot of overlapping but the emphasis differs as yleensä indicates that something is widespread/typical whereas tavallisesti points out that something is normal, regular, standard.