mislead The other three are wrong and imply that it is your speech that has made the error. A speech can mislead sb. It can be mistaken, misunderstood. A person can miscalculate, but a speech can only show a miscalculation, not perform one itself.

The word you should use is "misled". I think the sentence would sound better if you said: I am afraid that my speech may have misled you as to my true intentions. I believe that this means the following: The person who is speaking has said something and he fears that the other person has been misled or interprets the conversation in the wrong way, not as he intended. For example a man may say to a woman coworker " You look very nice today." Then the woman may think that he is flirting with her. She might ask him to get drinks together after work. Then the man can say " I am afraid that my speech may have misled you as to my true intentions. I was just complementing you, I was not aiming to have drinks with you" * Please tell me if this helps, does it make sense now?