There are also some examples of more difficult and idiomatic words and phrases like "nowt" and "How are things?" that students would probably still understand from the context. How do you feel about using these in your classes?
If you use natural sentences at natural speed students will hopefully learn to guess the meaning from context, to accept not understanding every word, and to remember language in longer stretches rather than word by word. They might, however, never understand what the individual words are and might never be able to tie it in with the language on the syllabus. Which of these are more important for your students, do you think?