Non-native speakers of English usually carry some of their native language over to English. While this often makes English sound beautiful, it can also cause problems with communication. Depending on your knowledge of how we make sounds and how one language is different from another in which sounds are used in words, it can be a challenge to be understood.
If you are looking for help developing better comprehension from native English speakers (especially if you communicate over a telephone), please check the links below:
Especially for non-native speakers, these two videos do a great job of explaining how to make your speaking understandable to your audience
when you learn these phrasing techniques, your speech will FLOW much better.
In this video, there is good information about FUNCTION words and CONTENT words that give you tips on how to find the words to stress, but about the FOUR MINUTE MARK she gives lots of good examples. http://www.youtube.com/watch?v=Wbs5aoqFtVQ
and of course my favorite (about the one minute mark for projection and breathing) https://www.youtube.com/watch?v=9bQlOvUSN_c
but do not forget that you can search youtube for more examples!