ALPHABETICAL INDEXING LANGUAGES
In this section let us look at the concept of indexing language, its categories and functional use. Let us begin with the meaning of 'indexing language'. It is the language used to describe a s0ject or other aspects of information in an index or in a library catalogue. The generally accepted difference between a library catalogue and an index is that an index entry merely locates a subject or a concept, whereas a catalogue entry includes some descriptive specification of a document containing the subject. But the line of demarcation is not, in practice, hard and fast. The indexing language can be an alphabetical language or may be a classification scheme. But, our emphasis would be on alphabetical indexing languages. There are three main categories of indexing, languages. They are:
a) natural indexing languages;
b) free indexing languages; and
c) controlled indexing languages.