Can you tell me if these two verbs "to lighten up" and "to settle down" mean the same thing in this sort of sentence and if they can be used
indifferentlyinterchangeably in sentences like these ones? Well...., it depends on context as always.
1) Enought talk about business. Let's lighten things up/settle things down round here. In this context I get the sense "lighten up" would suggest simply that the speaker wanted to get off discussion of business related issues and talk perhaps about the upcoming holiday, for example. On the other hand, to use "settle down" would suggest to me, again in that context, that the business discussion was becoming heated or argumentative.
2) Settle down/Lighten up guys. You've been talking about death and coffin all night! Same as above. I would use "lighten up".
3) Stop talking like this and don't be so hard on yourself (yourselves)! Try to settle down/lighten up! Either could work. The person spoken to was excited.
Do you think that the two verbs above can be substituted by other phrasal verbs, such as "to calm down" and "to cool down" without turning upside down the meaning of the sentence? Either would typically be used when someone was excited or angry.
Thank you so much for the explanations.