OLAC Subject Terms and Their Equivalents

Library of Congress Subject Heading (LCSH) terms are constantly evolving, only usually have 3-6 applied to a single work, are comprised of morphological components (there are classes of terms—roots or stems which are called topics, and then modifiers “morphemes” which are called topical subdivisions). For discussion of the linguistics in the LCSH description language consider (Citation: Daily, 1957) Daily, J. (1957). The Grammar of Subject Headings: A Formulation of Rules for Subject Heading Based on a Syntactical and Morphological Analysis of the Library of Congress List .  Columbia University, Retrieved from https://www.proquest.com/openview/41ed2cde0a8ef9cd9f8bc132b91e82c6/1 , (Citation: Svenonius, 2000) Svenonius, E. (2000). LCSH : Semantics, Syntax and Specificity. Cataloging & Classification Quarterly, 29(1-2). 17–30. https://doi.org/10.1300/J104v29n01_02 , (Citation: Iwe, 2001) Iwe, J. (2001). Linguistics and Information Processing: Provision of Syntactic and Semantic Consistency in the Language of Library of Congress Subject Headings (LCSH) Pertaining to Literature and Librarianship: A Comparative Analysis. Cataloging & Classification Quarterly, 32(2). 107–126. https://doi.org/10.1300/J104v32n02_09 , (Citation: Anderson et al., 2006) Anderson, J. & Hofmann, M. (2006). A Fully Faceted Syntax for Library of Congress Subject Headings. Cataloging & Classification Quarterly, 43(1). 7–38. https://doi.org/10.1300/J104v43n01_03 .

In contrast to LCSH subject terms, the Open Language Archives Community metadata schema, a Dublin Core profile designed to be shared over OAI-PMH has only 29 subject terms. The small number of terms (set size) and their apparent clarity to linguists are some of the great aspects of OLAC, where content creators are often the ones who also are cataloging the materials. Of the 29 OLAC subject terms listed in the OLAC documentation, the documentation indicates that 22 of them are matched to LCSH terms. Generally the OLAC note says: “The category is equivalent to the Library of Congress subject heading of the same name.” However, no specific LCSH term is specified. This creates problems for libraries who might otherwise use their LCSH terms to propagate OLAC terminologies for use in the OLAC aggregator.

Several examples are worth mentioning:

1. phonology. The OLAC term for phonology says that there is no equivalent term in the LCSH schema. I find this ridiculous, untrue, but yet understandable. Within the LCSH system Phonology is a topical subdivision term. Meaning it is a “morpheme” which combines with qualified topic terms. So, the concept exists within the LCSH system, but not independently. The most general phonology term in the LCSH system is a complex term Grammar, Comparative and general--Phonology which does not have a referenceable URI, further complicating equivalency mappings in crosswalks.
2. lexicography The OLAC term for lexicography says that it is equivalent same term in the LCSH schema. However, there are two terms in LCSH for Lexicography. It is not clear which one OLAC means. As mentioned previously, LCSH terms exist in different classes (roots and “derivation” morphemes). The root topic concept is sh85076357, but the general subdivision one would is sh99005001. It is probable that OLAC refers to the topic (root) rather than the general subdivision term. However, for clarity these things should be overtly stated.^1,2
3. philosophy_of_language. It is entirely unclear which LCSH was seen as corresponding to OLAC’s philosophy_of_language subject tag. The OLAC documentation suggests: “The category is equivalent to the Library of Congress subject heading of the same name.” However, I become confused as there does not seem to be an exact match at the Library of Congress. The closest terms I can find within the LCSH terms are as follows: Philosophy (a topic term), Linguistics–Philosophy (a complex term; linguistics is the topic and the sub-topic is philosophy), Language and languages–Philosophy (the sub-topic philosophy is used under a different topic Language and languages), or in my opinion the least likely case Ordinary-language philosophy.

For the OLAC subjects I have looked at already, the following table lists what I hypothesis as being the OLAC intended equivalent. I haven’t worked my way through the whole table yet. When I have worked through the whole set of OLAC terms I will present this data in a more beautiful way. Currently it is in a markdown table and as a JSON file.