This site is maintained by the University of Iowa. It offers audio and video of spoken English, as well as Spanish and German languages. A mobile app is also available.
"The Visual Dictionary is designed to help you find the right word at a glance. Filled with stunning illustrations labeled with accurate terminology in up to six languages, it is the ideal language-learning and vocabulary dictionary for use at school, at home or at work." (from: http://www.visualdictionaryonline.com/about-visual_overview.php)
Purdue Online Writing Lab (OWL): ESL Students
"These OWL resources will help ESL students in second language writing. This section includes resources on writing across the curriculum, writing in the disciplines, and it contains links to OWL workshops and exercises useful for ESL students. This section also includes links to ESL resources on the Internet." (from: https://owl.english.purdue.edu/owl/section/5/25/)
Purdue Online Writing Lab (OWL): ESL Tools
Provides materials for ESL students and teachers.
"The internet's meeting place for ESL + EFL teachers + students around the world! (from: http://www.eslcafe.com/)
"The Oxford English Dictionary (OED) is widely regarded as the accepted authority on the English language. It is an unsurpassed guide to the meaning, history, and pronunciation of 600,000 words— past and present—from across the English-speaking world." (from: http://www.oed.com/)
"These pages contain free online practice tests for the most important international ESL exams." (from: http://www.examenglish.com/)
"A completely free open source site ideal for blended learning: original videos, interactive lessons, an English teacher always present to help you, and a community of teachers & students learning together." (from: http://www.real-english.com/)
Antimoon : How to learn English Effectively
"A guide to learning English really well. Covers motivation, dictionaries, pronunciation, input, and more." (from: http://www.antimoon.com/how/pronunc-soundsipa.htm)
Adult Learning Activities : California Distance Learning Project
"Use this free site to build your reading and life skills." (from: http://www.cdlponline.org/)
"A free website for adults to learn English. Here you can practice English speaking, reading, writing, listening, grammar, vocabulary and more." (from: http://www.usalearns.org/)
"Interesting things for ESL students." (from: http://www.manythings.org/)
Maintained by the Internet TESL Journal. Links of interest to students and teachers of English as a Second language.