Types of Indexing Language

1. Natural Language (derived term system)

Characteristics are:
Improves recall because it provides more success points but reduces precision
Redundancy is greater
Uses more current terms
May also be called Indexing by Exyraction

2. Controlled Vocabulary (assigned term system)

Functions:
To control synonyms by choosing one form as the standard term
To make distinctions among homographs
To bring or link together terms that are closely related
Establishes the size of scope of a term