People take their coffee seriously. For many it’s a highlight (or several) of the day, and woe betide anyone who serves them an inferior cup. Fussiness over the taste of coffee is matched by fussiness over its terminology – though the fussers aren’t necessarily the same people. Ask for an expresso in public and you’ll put frowns on the faces of perfect strangers. Some will judge you, silently or otherwise, for not saying espresso with an ‘s’ instead. But should you? And why are both words used?
Espresso comes from Italian caffé espresso, and means ‘pressed out’ – the coffee is made by pushing pressurised water through the beans. But because it’s so similar to English express, which often refers to a rapid service (express train, express delivery, express lane), there’s a common belief that it has to do with speed – an espresso as a quick coffee on the go. So the ‘x’ infiltrates the spelling and pronunciation of espresso, leading to expresso.
Another reason for the popularity of expresso is that it looks and sounds more like an English word than espresso does – albeit an imported one, with that ‘o’ at the end. Aside from esprit, another Romance-language borrowing, espresso is the only word in common use in English that begins with espr-, whereas expr- is very familiar from words like express and expression. So people unconcerned with etymology are unlikely to notice anything wrong with expresso. In any case, the two forms overlap when traced back far enough: espresso ultimately derives from Latin exprimere ‘press or squeeze out’.
Usage purists are not happy about expresso being in common use. To them, it’s wrong, end of story, and anyone who uses the word is making a careless linguistic error and a social faux pas. This may seem a reasonable stance. But expresso has been in print since at least 1955 (appearing first in the New York Times, no less), which is almost as long as espresso has been in the language.
Oxford Dictionaries calls expresso ‘incorrect’, but the OED, Merriam-Webster, American Heritage Dictionary, and Macmillan Dictionary all list it neutrally as a variant. Copy-editors and proofreaders will keep the variant spelling’s numbers down somewhat in published texts, but in speech and casual writing you can expect it to hold its own. If expresso continues to establish itself in general usage, it will eventually be accepted as standard by all but the most conservative critics.

For those of you who read Italian, Licia Corbolante wrote about this on her Terminologia blog: http://blog.terminologiaetc.it/2013/04/17/internazionalismi-prestiti-parziali/
If it’s any consolation, there are at least three different Italian spellings for the word “tea”, that is: “tè”, “the” and “thè” – with the first one being the “preferred” option according to dictionaries.
Anyway, to get back to your “espresso”, this could sound like some sort of linguistic nemesis but, whereas in English you can easily turn this loan word into a plural by adding an “–s” (“espressos” or “expressos”), things aren’t as straightforward in Italian. Some sources would class “espresso” as invariable, hence “2 espresso” whereas others would see it as a noun and decline it accordingly, hence “2 espressi”. In the convivial context of the Italian bar culture, this dilemma has however been effectively bypassed: customers would ask the barista for “caffè” as opposed to “espresso”, given that there’s no need to specify.
In Italian, “espresso” recalls the idea of something “fast”, most likely from the express postal delivery and the express train service, called “espresso” in Italian too. So the “press out a liquid” meaning has somehow gone lost in this metaphor, much more than in English. As a non-native speaker of English, I’ve always found the collocation “expressing breast milk” puzzling, as we wouldn’t share it in Italian.
Curiously, when looking up “espresso” in Italian dictionaries, most definitions make reference to “a coffee expressly prepared”, with “expressly” having the meaning of “by the customer’s specific request”.
So, isn’t it amazing that “espresso” simultaneously carries out the meanings of “pressed out”, “quickly” and “specifically”?
A word like this definitely deserves more than one spelling.
Thanks for your very interesting comment, Geraldina. It’s great to get an insight into these conventions. And I can’t help but agree with your conclusion. So many nuances and connotations add up to a surprisingly complex word: let’s allow it some orthographic variation.
Somewhere – perhaps here – there’s a thread about ‘latte’, which presents a similar problem.
The purists seem to me completely wrong here. Once a word is adopted into the language it must be allowed to settle down into the sound range of English.
This is a particularly egregious example of purism being a form of snobbery.
I agree, Bev. It seems especially common with foodstuffs (including coffee types), because of the great range of words imported from that domain. Articles on ‘food words you’re pronouncing wrong’ are a popular form of clickbait but seem to me just a way for some people to look down on others because they aren’t in the know about a word’s pronunciation in its original language. I’m glad to see that Macmillan’s entry for quinoa, for example, has a common anglicised pronunciation alongside the pedantically preferred form.
Bev, Stan: These are really interesting comments about varying prounciations, and which should be given in dictionaries. We quite often add foreign borrowings to the dictionary – most recently, words from Philippine English – and it can be quite tricky deciding which pronunciations to give and how far to try and approximate the original prounciation. I’m glad we got ‘quinoa’ right.
Thanks, Liz. I’m all for including as many valid options as seems appropriate! People take their cue from authorities like dictionaries (no matter how lexicographers feel about that), so when those authorities record multiple ways of saying a word, users are less likely to succumb to the One Right Way fallacy.