The web site of the Linguistic Society of America contains a section "What is Linguistics" that contains a large number of pamphlets written by well-known linguistics on topics ranging from "multilingualism", to "language variation and change", to "language acquisition".
This is the main listserv in the field of linguistics. You may search the archives of the Linguist list for any topic in language that interests you. There is a high probability that it has been discussed on the list at some time. There is also an "Ask a Linguist" section: linguistlist.org/ask-ling.
This is the web site of the American Dialect Society. Its listserv contains discussions of a large range of topic. The "Words of the Year" section makes interesting reading.
This is a free dictionary of linguistics (modeled on Wikipedia) under the direction of Sven Naumann and Jan Wohlgemuth. It is not complete but already has many helpful entries.
The Oxford English Dictionary is the premier source of information about English vocabulary. Libraries often have subscriptions to the online version, which may be searched electronically.
The Phrase Finder provides both an online thesaurus of phrases and sayings and a bulletin board that allows you to query the origin of a phrase or saying.
Peter Ladefoged's online version of his books A Course in Phonetics, 5th edn., and Vowels and Consonant, 2nd edn., provide a wealth of material on English phonology, including pronunciations.
Designed by Daniel Currie Hall, this website shows the position of the articulators for the different speech sounds along with the relevant IPA symbol.
The Compleat Lexical Tutor is a web-based tool that can assist language learners in their acquisition of vocabulary. It includes a wide range of features such as a concordance, a word frequency list, and a cloze passage generator.
Lognostics, maintained by Paul Meara, provides useful tools for those interested in vocabulary acquisition research with second language speakers. The archives contain most of what has been written on second language vocabulary acquisition since the 1970s.
This is the website of New Zealand Applied Linguist Paul Nation, known for his work on vocabulary acquisition. Here you can download the General Service List and the Academic Word List, among other useful vocabulary resources.
The British National Corpus contains a wide variety of spoken and written samples of British English from a wide range of sources. The BNC may also be accessed from Mark Davies' web site: corpus.byu.edu/bnc
Mark Davies of Brigham Young University has designed a range of user-friendly, online corpora, including the Corpus of Contemporary American English (used in this textbook), the Time Corpus, the Corpus of Historical American English, the Strathy Corpus (of Canadian English), and several others. One may also access a portion of Google Books via his website.
"The Grammar Lab" is a set of four excellent tutorials on using the Corpus of Contemporary American English, including one tutorial on prescriptive and descriptive grammar.
The International Corpus of English is an international project that allows users to search corpora of regional Englishes around the world, both spoken and written.
This website is maintained by The Language Samples Project (LSP), a project developed in the Anthropology Department of the University of Arizona. It gives information on a number of British and North American varieties.
This link presents the results of a dialect survey of over 30,000 U.S. English speakers targeting pronunciation of certain lexical items and lexical choice.
This website provides a comprehensive discussion of Estuary English, a developing dialect of British English in and around London and the southeast of England.
The Speech Accent Archive reproduces the accented speech of speakers from many different language backgrounds (both native and non-native English speakers) reading the same sample paragraph.
In this YouTube channel from Macmillan Education, renowned applied linguist David Crystal presents a series of illuminating short talks on global English.
This is the website of the Animal Language Institute, whose mission is to promote a deeper understanding and appreciation of the communication systems of other species.
This article on "Animal Minds", from the National Geographic website, provides up-to-date information on research that is being conducted on animal communication.
In this TED talk, the internationally recognized authority on the primate world Jane Goodall notes that all that separates humans from primates is human's sophisticated use of language.
Behavioral ecologist Peter Tyack studies acoustic communication in whales and dolphins. In this TED talk, he explains how these animals communicate via sound and song.
In this Ted talk Susan Savage-Rumbaugh discusses the breakthroughs that she has made working with bonobo apes, who show a great capacity to understand human language.
This is the website of The Gorilla Foundation, dedicated to the study of gorilla communication. Here you can find information on Project Koko, a most comprehensive interspecies communication study involving humans and gorillas.
This blog, run out of the Institute for Research in Cognitive Science at the University of Pennsylvania, contains commentary on a wide range of issues related to language and cognition.
The blog Vocabulogic is maintained by Susan Ebbers along with guest contributors. In addition to its regular blog posts on vocabulary, the site contains an extensive list of links on blogs and online tools, morphology and etymology, and resources for teaching English language learners.
Citizen Sociolinguistics is maintained by Betsy Rymes at the University of Pennsylvania. The blog explores everyday encounters with language, examining different ways of speaking and attitudes toward these differences.
This blog from the international organization Teachers of English to Speakers of Other Languages covers issues of socio-political importance for TESOL teachers as well as pedagogical tips for working with English language learners.
New York State's affiliate of the international organization Teachers of English to Speakers of Other Languages provides a wealth of links for teachers of English as a second/foreign language.
California's affiliate of the international organization Teachers of English to Speakers of Other Languages provides numerous links of interest for teachers of English as a second/foreign language.
The British Council's website provides access to publications, lesson plans, webinars, professional development resources, and a host of other useful resources.
This guide to grammar and style compiled by Jack Lynch of Rutgers University contains helpful guidance for writing papers along with a list of useful style manuals.