The function of the infinitive phrase in the sentence <em>To win a marathon is my goal </em>is object of the verb.
It is definitely an object, and it would follow a verb if it were a normal ordering of words in the sentence (My goal is to win a marathon), and since it is not preceded by a preposition, it cannot be object of the preposition, but of a verb.
Answer:
If it were me, I'd pay attention to the speaker's gestures and facial expression. It's not in here, but I'd also include the tone of their voice.
Explanation:
Imagine, if you were listening to someone give a speech and they stood there with no emotion or movement, you're most likely not going to pay much attention to that person. In order to get the audience involved, it's best if the speaker gives some kind of gestures and feelings to get a response from the crowd. Make sense?
I hope this helps! Have a good day!