  There is an increasing interest and effort in preserving and documenting
endangered languages. Language data are valuable only when they are
well-cataloged, indexed and searchable. Many language data, particularly those
of lesser-spoken languages, are collected as audio and video recordings. While
multimedia data provide more channels and dimensions to describe a language's
function, and gives a better presentation of the cultural system associated
with the language of that community, they are not text-based or structured (in
binary format), and their semantics is implicit in their content. The content
is thus easy for a human being to understand, but difficult for computers to
interpret. Hence, there is a great need for a powerful and user-friendly system
to annotate multimedia data with text-based, well-structured and searchable
metadata. This chapter describes an ontology-based multimedia annotation tool,
OntoELAN, that enables annotation of language multimedia data with a linguistic
ontology.
