I've been listening to a lot of student talks recently. Often the content of the talks that I listen to are very good, but the content is difficult to get to because the pronunciation is poor! And the more I listen the more important I think it is that English language students understand the nature of STRESS in English. When native speakers are listening to non-native speakers of English we are quite tolerant of individual sounds that are not produced correctly, but we are less tolerant of differences in stress. One of the most important features of English that second language speakers need to be aware of is that English is a stress timed language. It sounds very technical, but it isn't. It just means that we stress the important words and all the other words get squeezed in between those important ones. So that these sentences:
Dogs chase cats
The dogs chase the cats
The dogs will be chasing the cats
all take the same amount of time to say. This means that many words have strong forms (when they are important and stressed) and weak forms (when they are not important and squeezed into the rest of the sentence).
I think the awareness of this is really important because then students can start to get away from the staccato pronunciation that impedes communication. The first step is to understand the nature of this feature of English and you can do that by taking a look at a couple of youtube clips which explain it well. Xansworld and Rachel's English. Com have some nice short explanations which make it clear. Thanks to youtube again!