Longman Dictionaries offers a wide variety of exercises focusing on different aspects of word meaning and use to improve your vocabulary.
The Oxford 3000 is a list of the 3000 most important words to learn in English, as selected by a group of language experts and experienced teachers.
Listening Practice
EnglishClub provides audio recordings and resources to practice your listening skills.
English Listening Lesson Library Online (ELLLO) offers over 2,500 free listening lessons. Teachers and students can access lessons for both beginner, intermediate, and advanced students.
ESL Gold offers a variety of listening resources by level, including videos and links to podcasts for English language learners.
Rachel’s English has nearly 400 videos to help you improve your spoken English and listening comprehension.
Randall's ESL Cyber Listening Lab provides online English listening comprehension quizzes and activities by level (easy, intermediate, difficult).
Pronunciation Practice
EnglishClub offers lessons and resources on the way we say words in English, many with audio for you to listen to.
Longman Dictionaries offer exercises that focus on sounds, syllables and stress in words to improve your listening and pronunciation skills. You can also test yourself on some of the common differences between British and American pronunciation.