1) they are very close in meaning. In common usage, both imply that you started trying in the past and are continuing in the future. However, "I am trying" stresses that is is going on now and "I have been trying" stresses that it was happening in the past. 2) you have a choice: "I didn't respond to you." or "I didn't answer you." The first needs the "to"; the second can't have it.

"I have been trying" emphasizes an effort that started in the past and continues on today. On the other hand, "I am trying ..." simply expresses a current situation without any reference to the past. So which one is "better" depends on what you are trying to express - an effort that started in the past and continues presently, or something that is occurring right now (without referring to the past). Now, for "respond you" versus "answer you" - note that both verbs are equally correct, but "respond" requires the preposition "to." In other words, it is either "respond to you" or "answer you." Again, however, there is a difference in nuance. "Respond to" can mean that you provided a response without giving an answer. However, "answer" can mean to provide a solution, rather than merely to provide a "reaction" to something/someone. That is, in response to the question "Have you seen John today?" A "response" could be "What did you say? I couldn't hear you!" An "answer," however, could be "Yes, I saw him in English class." Hope this was helpful! :)

Hi ! I would like to be your partner for practicing languages :) English, French and Spanish if you want :) I'm native in Spanish. Thanks! :)

Business Ed is right on! Here are ways I would say these phrases. "I've been trying to talk a bit with some of my friends" "I've been trying to talk some with my friends" "I've been trying to visit with my friends" ----say these, for example, to your companion as you explain that you attempted to make contact with your friends earlier today. "I am trying to speak a bit with some of my friends" "I am trying to talk some with my friends" "I am trying to visit with my friends" ----say these, for example, to your companion who is making noise around you when you are speaking with your friends on the telephone