We have several encyclopedias, both multi-volume and single. Among the former are included the Encyclopedia of Cultural Anthropology (Ref. GN 307 .E52 1996). It's best to use the index in the fourth volume. For example, "Phonemes" would be found under "Descriptive Linguistics." Next is the International Encyclopedia of Linguistics (Ref. P 29 .I58 2003), also a four-volume set, with index in vol.4. The set is alphabetically arranged by topic. The entries are essay length and written by an international team of scholars. The set attempts to include the whole range of linguistics. Encyclopedia of Language and Education (Ref. P 40.8 .E53 1997) is an eight-volume set with each volume devoted to a topic such as applied linguistics or language theory. Each book consists of essays written by different scholars. Chapters are about 3000 words with references. The Concise Encyclopedia of Sociolinguistics contains " contains articles, including short biographical entries, providing uniquely comprehensive and authoritative coverage of all aspects of sociolinguistics. " Here are some other online Encyclopedias:Encyclopedia of Communication Theory;Encyclopedia of Cognitive Science.
Moving on to single volume titles we have The Linguistics Encyclopedia (Ref. P 29 .L52 2002). With some exceptions, entries are about five pages. There is a list of subjects in the front and an index in the back. Language and Communication (Ref. P 29 .F 47 1998) is a slender volume of essays that treat language from a cross-cultural perspective. Here one will find entries on such topics as say, "Backchannel Cue" or "Cocktail Party Effect." The Cambridge Encyclopedia of Language (Ref. P 29 .C64 1997) is arranged by sections, such as "Child Language Acquisition," with chapters on "Grammatical Development" or "The Languages of the World" and chapters on "The Origins of Language." Chapters are about 5 pages. The Concise Encyclopedia of Educational Linguistics (Ref. P 40.8 .C66 1999) "aims to present any knowledge from linguistics...that may have a bearing on the education of children and adults." (p. 1) Its scope is thus broad: "Society," where one will find essays on "Diglossia" or "Language Loyalty" or "National Policy" with chapters on various countries' language policies. There is also a Cambridge Encyclopedia of the English Language (Ref. PE 1072 .C68 2003). Try the MIT Encyclopedia of the Cognitive Sciences (Ref. BF 311 .M556 1999). The International Encyclopedia of the Social. Sciences is now online.Click here.
The Concise Oxford Dictionary of Linguistics (Ref. P 29 .M34 1997)
Dictionary of Linguistics and Phonetics (Ref. P 29 .C65 2008; 2003 edition available online)
Routledge Dictionary of Language and Linguistics (Ref. P 29 .B875 1996)
An Encyclopedic Dictionary of Language & Languages (Ref. P 29 .C68 1992)
Glossary of Linguistic Terminology (Ref. P 29 .P39 1966)
Dictionary of Languages (Ref. P 29 .D35 1998; 2006 edition available online)
A Glossary of Sociolinguistics. (Ref. P 40 .T747 2003)
A Glossary of Language and Mind. (Ref. P 37 .A374 2003)
Some other online dictionaries include:
The Atlas of North American English: Phonetics, Phonology and Sound Change. (Ref. PE 2808 .L26 2006)See also: A Map of Languages in the United States.
iLoveLanguages: Your Guide to Languages on the Web
Identifies 74 resources in linguistics.
Linguistic Resources on the Internet
Covers morphology, speech and phonetics, grammar and syntax, etc.
Yale University Library Linguistics
Useful for other gateways and online publications.
Subject arrangement, such as language acquisition, semiotics. Includes other site listings.
Center for Applied Linguistics
Has a search engine and covers these topics:
Center for Spoken Language Understanding's Current Corpora
Online Periodicals, Surveys, and Newsletters
SIL Serial Publications And Journals Good for table of contents and back issues.
Other Internet Sources
Ethnologue: Languages of the World. Good for language names, families and codes.
BUBL LINK Linguistics. A few gateways here but mostly topics.