Complex sentence: The Moravians are a Slavic ethnic group who speak various dialects of Czech, but few Moravians assert, the Moravian is a distinct language, however, their efforts are not widely supported by academics and the public.
Split into simpler sentences: The Moravians are a Slavic ethnic group who speak various dialects of Czech. Some Moravians assert that Moravian is a distinct language, however, their efforts are not widely supported by academics and the public.