Never interrupt them when they are talking.

当他们谈话时，千万不要打断他们。

Also, it's rude to interrupt Japanese people while they are talking to you.

此外，在日本人和你说话时打断他们是不礼貌的。

They are talking in whispers over there.

他们在那儿叽咕着。

They are talking in whispers. / They are talking in a low voice.

他们在悄声谈话。

They are talking in French.

他们在用法语交谈。

They are talking a sore point

他们在讨论一个惹人恼怒的话题

They are talking to a policewoman.

他们在和一个女警察讲话。

You seem what they are talking about.

你好像知道他们在谈论什么。

They are talking happily in the office.

他们正在办公室开心地说话。

They are talking about an Amerian movie.

他们正在谈论一部美国电影.