You may not know it, but every time you use that expression, you’re speaking French. Well, that’s pushing it a bit, but this perfectly good English phrase is actually a borrowing from French.
Most people realize that languages bump up against one another pretty regularly, and as a consequence, there are lots of loanwords, or borrowings, from different languages. This phenomenon is often relatively easy to spot. You know that cuisine, café, banshee, zeitgeist, glasnost, and tsunami are red-blooded English words, but they’ve clearly come to us from “somewhere else.”
It can get a bit complicated, as things often do, when you dig deeper and sort through the types of borrowings. Are they still “foreign” in spelling, and perhaps elements of pronunciation? Have they been shaped by (in this case) English spelling and pronunciation so that they can pass as native English words? Are they single words, or phrases? And in the case of the second, are they literal translations, or partial renderings from the source language? Linguists who study languages in contact love to tease all of this apart. For an intro to the basics, you can read this Wiki article on loanwords, or this more general one on language contact.
Back to the point of this post, it probably doesn’t actually go without saying, for most of us, that this is a borrowing from French. In technical terms, it’s a calque, or a literal, word-for-word, root-for-root, or, if you like linguistic terminology, morpheme-for-morpheme translation. The phrase in French is ça va sans dire, which, literally translated, is that/it goes without saying. (If you’re reaching for your e-mail to correct me by pointing out that dire is to say, not saying, I’d point out that French uses infinitives where English uses gerunds, so it still counts as literal.)
An obvious question you might ask is how can we be sure that it goes without saying is borrowed from the French ça va sans dire? The problem with calques is that they express concepts that could certainly be universal, or at least not confined to one language. So, isn’t it possible that the two phrases, one in French, one in English, arose perfectly independently of each other to express something that human beings, whether they drink tea or wine, feel a need to express? Sure, it’s possible, and to prove that something is truly a calque, you need to come up with some historical evidence or point to traces of “foreignness” in structure. Because, more often than not, it doesn’t go without saying! - Chris