So what I've heard is that (like most cases) the more you add in, the more it's emphasized. So 我们在说话。Would be pretty neutral: we are talking, whereas 我们正在说着话呢。Would be like: we're talking right now! (so go away or something). Otherwise I think they are pretty much the same. But you should double check with a native speaker.

If someone is asking you “what are you doing ?” Your answer can be more naturally by using "我正在......呢"

妈妈在晾衣服。 妈妈正在晾衣服。 妈妈正在晾衣服呢。 下面这一种说法很少使用： 妈妈正晾衣服。

这几句话，意思一样，没有什么区别。

Thank you for answering.