There is provided an identifier dictionary-generating device for use in a system for reversely producing specifications expressed in a vernacular language from a high-level language program. The identifier dictionary-generating device extracts alphabetic identifiers of variable names and corresponding vernacular identifiers, to form an dictionary of identifiers. The identifier dictionary-generating device is comprised of a word fetching device for fetching words from the high-level language program, a first identifier extracting device for extracting a first identifier from words fetched by the word fetching device and a second identifier extracting device for extracting a second identifier in a vernacular language from the words fetched by the word fetching device, and a registering device for registering the first identifier and the second identifier into the dictionary when the first identifier and the second identifier corresponding thereto are extracted. The dictionary containing variable names dentifiers in alphabetic characters and vernacular identifiers provided in a manner correspondent thereto can be prepared by setting the first identifier to an alphabetic identifier as a variable name, and the second identifier to an identifier obtained from a comment in a vernacular language annotated on the variable name.