Our Grammar and Composition site is intended to assist all students of English--native speakers and non-native speakers alike. That said, speakers of English as a Second Language (ESL) often have special interests and require more extensive treatment of certain grammar-related topics, such as idioms, articles, and prepositions. Those interests and topics are best dealt with at websites that focus on the needs of ESL students. Here are four superior websites (all of them free) for students and teachers of English as a Second Language.
For more than 15 years, Kenneth Beare has hosted this extensive ESL site at About.com. Lessons are categorized according to skill level (beginning, intermediate, and advanced), and special pages have been developed for ESL teachers. In addition to treating grammar and writing skills, the site contains particularly strong articles on listening skills, vocabulary development, and pronunciation.
2. ESLpointOne of the largest online resources for students and teachers, ESLpoint provides links to thousands of pages of ESL-related materials, all categorized according to skill and difficulty.
This frequently updated site includes links to "hundreds of other high-quality, free ESL/EFL sites and resources."