The Slavic languages are more similar to each other than are the Romance languages, especially in respect to their basic lexicons, phonologies and morphological structures. Cassubian is sometimes treated as a distinct language, but within Poland it is felt to be a dialect of Polish. It uses numerous diagraphs, and diacritics on certain consonants and vowels.
Some variation exists in the spelling of some sounds.
Nouns which are feminine, masucline, and neuter are declined in four declensions, and adjectives in one. The seven inflectional cases are nominative, accusative, genitive, dative, instrumental, locative, and vocative. Another distinciton in the case system is between masculine personal and nonmasculine personal nouns and adjectives. There are, however, honorific second person pronouns which are used with third person forms of the verb. In syntax, main verbs agree in person and number with their subjects.