One common misconception about Deaf and Hard of Hearing individuals is that each one is able to lip read effectively. Although in some cases, DHH individuals have developed this skill to a certain extent, being able to read lips is a complex skill that is influenced by a variety of factors. Watch the video, "What It's Like to Read Lips", to get a sense of the complexity of the skill and to understand what your DHH students may be experiencing.
Below is a link to an article from the Victorian Deaf Society, located out of Australia. In this article, the four main issues in speechreading (lipreading) are discussed and how to best address these issues to ensure communication is not lost between the DHH individual and those they are trying to communicate with.