The Evolution of Grammatical Categories

If from the etymological point of view the term category denotes a class of objects sharing a common feature, under linguistic category we generally understand a class of linguistic units (chiefly words) sharing a common meaning or syntactical function, expressed by a common external (phonetic) form. Thus the words room-s, table-s, pencil-s, match-es, glass-es… are representative of the category of the plural number; ( be ) describe-d, contrive-d, share-d, found-ed, assert-ed… represent the category of the past tense. Forms like men, children , etc., on the one hand, (he) rode, went , etc., on the other, are also members of the category of the plural or past, respectively, in spite of the lack of the characteristic feature -(e)s or -(e)d , since functionally (i.e. as regards meaning) they lean upon the pattern of the productive -s and -d forms, thus: the semantic difference between man and men ( child and children ) is the same as that between e.g. room and room-s , rendered by the sign -s versus zero; the semantic difference between rides and rode ( goes and went ) is the same as that between describe-s and describe-d , rendered by the sign -d as against -s .