说回来用英语怎么说

To say it in English, you can use the phrase "to put it in English" or "in other words." This phrase is commonly used when someone is speaking or writing in one language and wants to express the same idea or concept in a different language.

For example:

我想说的是，也就是说，这个问题很重要。 (In other words, the problem is important.)
我们可以用英语来表达这个想法，换句话说，这个计划非常可行。 (We can express the idea in English, in other words, the plan is feasible.)

It is not clear where the phrase "to put it in English" or "in other words" originated, but it is likely that it came into use as a way for people to express their ideas in a different language when speaking or writing to an audience that may not understand their native language.