（有人听到）他冲着那2个抓住他的人大声的咒骂着。 我想知道谁在冲着谁叫骂？ I hope you can tell us which language you wanna translate to in title, cause I'm not sure about that until I saw your profile.

He could be heard swearing at the two men who caught him.能听得到他在骂两个抓他的人。 I want to konw who is swearing at who? 我想知道谁骂谁呢？

We often say some sound could be heard, such as: Her laughter could be heard out of the room. Some noisy could be heard at the staircase. We could also say someone could be heard, such as: He raised his voice so that he could be heard clearly. In your question, it's a passive sentence, 'he could be heard' indicates that it's he who make the sound, and he could be heard by someone else. You could simply say: He is swearing at the two men who caught him.

Two men caught him. The man who was caught could be heard swearing at the two men.