Shahin
To return to one's mutton (idiom) I had not heard of this expression until somebody (a language partner from this site in fact) mentioned it, and it turns out it is an old English saying that comes from a French expression. It means to return to the matter at hand.

I wonder, had anybody heard of this expression before this post? It is outdated I believe, but I am nonetheless surprised that I had never heard of it before!

May 30, 2019 1:07 AM
Comments · 2
Thanks Jérémie. I meant it is an outdated saying in English. Indeed the French influence upon the English language is great and also undeniable, but this particular expression is uncommon I believe, for it was the first I heard of it.
May 30, 2019

 It is not outdated, I have heard about it, and we use it very often, here in Quebec.I seldom have seen it being used in English though, a lot of English words and expressions come from French, I suggest you to look into the history of the Norman Conquest and the consequences of it on the old English society; 30% of English words come from French and especially, Normand French. 

https://medium.com/@andreas_simons/the-english-language-is-a-lot-more-french-than-we-thought-heres-why-4db2db3542b3 ;

May 30, 2019
Shahin
Language Skills
Arabic, English, Italian
Learning Language
Arabic, Italian