The Czech and Slovak languages form the Czech–Slovak (or Czecho-Slovak) subgroup within the West Slavic languages. Most varieties of Czech and Slovak are mutually intelligible, forming a dialect continuum (spanning the intermediate Moravian dialects) rather than being two clearly distinct languages; standardised forms of these two languages are, however, easily distinguishable and recognizable because of disparate vocabulary, orthography, pronunciation, phonology, suffixes and prefixes. The eastern Slovak dialects are more divergent and form a broader dialect continuum with the Lechitic subgroup of West Slavic, most notably Polish.