Give them some tasks. If they understand it, get them to listen or watch something and then report it back. If you can shift the focus to making them produce, then they'll improve. Try not correcting them, but making them reforumlate things and expertiment to get their message across. If you spoonfeed the answers, it may make them dependent on you. If they have to fall back on their own resources, however limited, they will have to start being more creative. Make them 'bring' \something new to class like a word or phrase that they have learned. They have to become active in their learning.
