1. both are correct, but have different meanings. 1) he did not try to speak English - this means that he was not trying, or making an effort to speak English. meaning that.. he is probably not an English speaker, and he did not make the effort to speak it. 2) he tried not to speak English - this means that he did try, or made the effort, to not speak English. meaning that.. he is probably an English speaker, but in that situation, he made the effort not to speak English. 2. both sentences are correct, and natural. you don't have to necessarily add -ing to the verb when you write in past tense. as for your last question.. it is better to say 'what is the difference between them?' if you find my answers confusing, tell me on MSN and i will try to explain it again! :)

hi 1.number one is correct & another is false( we just use not+ auxiliary verbs not all of verbs). 2.the tense of your sentence is simple past so the number one is correct & another is false. (if you wanna use - ing - in past time you have to use - tobe forms - too for example : i was reading ) 3.whats the diffrence is correct & better. thanks GOOD LUCK