This is not the place to go through all the problems that lecturers with English as their second or third language face due to interference from their native language.
It must be emphasised, however, that a wrong pronunciation of individual words – and not least technical terms – is threat number one to students’ grasping the information. A grammatical error and a badly chosen word now and then do not have the same negative impact on the students’ learning as has the pronunciation
If you are not sure how to pronounce a given word, check http://howjsay.com.
Many online dictionaries offer help, too. At http://www.bbc.co.uk/worldservice/learningenglish/grammar/pron/,you will find very good advice and good exercises.