1) ''I did ask them'' / ''I asked them'' 'Did' emphasizes the fact that he really did ask. Where as there is no emphasis in the second sentence. Look at these scenarios according to different stresses (capitalized) A. Did you not ask them ?! or I know that you didn't ask them. B. I DID ask them ! But they never responded. A. Whom did you ask ? B. I asked THEM. A. What did you do ? B. I ASKED them ****************************************************************************************** 2) ''I got tell you'' / ''I told you'' the first sentence is wrong, It should be " I got to tell you". This means "I must tell you" or " I Have to tell you". this signifies an action about to take place in future. the second sentence is however in the past and means that the person has already told the other person something. Look at the following scenario : A. Why are you running. What happened ? B. I got to tell you what I just heard. The king has ordered your arrest. ESCAPE ! A. Oh my god, really ?? B. I told you this would happen one day.

In the past, you don't have to put the auxiliary did, so, the correct is saying "I asked them", but, in some cases, people use the auxiliary did (it isn't very used) for emphasising. The other phrases, the first, is unfamiliar for me, so I can't say anything about it.