. . "Formal_language#Applications" . . "Formal Languages" . "Reversal" . "finite word" . . . . . "type formalism" . "informal" . "alphabet" . . "set of words" . "words" . . . "words over" . . "formal programming language" . . "formalization" . "formal terms" . . . "Languages" . "string" . "Formal language#Words over an alphabet" . "symbolic system" . "strings" . "formal language theory" . . . . . "word" . . . "language" . . . "formation rules" . "formal languages" . . "transformation rules" . . "Formal language" . . "Formal_language#Operations_on_languages" . . . . . . "Language" . "Formal language#Constructions" . "logical language" . . "formal language" . . "(formal) language" . "formal methods" . . . . "reversal" . "string of characters" . "Formal" . . . "Formal language" . . . "languages" . "formal" . "formalize" . . . . "formalized language" . .