I still recall, with a mixture of amusement and embarrassment, the time I took a visiting Italian friend to lunch in a café along London's Holloway Road. After studying the menu, he ordered a mozzarella and tomato panino – ‘so that'll be one panini for you’, jotted down the young woman behind the counter. My friend confirmed his choice by repeating it in a way that signified he could speak only for himself. And to make his point, he leaned somewhat on the singular -o of the ending, keen, I imagined, to avoid the kind of mix-up that leads to extra portions being brought to one's restaurant table in error. But to no avail: before proceeding to take his order, our waitress told my companion firmly, in an unmistakeably eastern European accent, that he would be having a ‘mozzarella and tomato panini’, and that was that.

Arguably, had the young woman serving been English she might not have shown any regard (albeit a misplaced one) for exactitude in the matter of word endings, nor indeed have been moved to make this hypercorrection, yet the fact that she did is a reminder of the increasing prevalence in the English language of Italian terms related to food, and of their often uncertain grammatical status. This is not to mention the semantic shifts they have undergone since being set adrift from their native moorings. Certain nouns which are generic terms in Italian (e.g. panini, biscotti) have acquired very specific denotative meanings in the mouths of English speakers.

Thus, a panino, when eaten in Italy, is not necessarily the grilled savoury snack with which we are familiar in this country, but any kind of sandwich, toasted or otherwise. It is also the name used to refer to all varieties of bread rolls that can be bought in a bakery. According to current English usage, encouraged by the (multinational) vendors of Italian-style beverages, a biscotto is commonly recognised as a sweet slab of something to accompany one's coffee; ostensibly a biscuit, but on closer inspection and contact it turns out to be a stick of rock, best kept away from one's front teeth. This is because the type of biscuit that English speakers automatically associate with the lexical borrowing biscotti is a very specific item, namely, those oblong almond biscuits known as cantuccini, or biscotti di Prato, that are deliberately hard; they are baked until they are crisp enough to be dipped in vin santo (a sweet dessert wine produced in Tuscany), and enjoyed after a meal, mainly by those who live in this region.

Panini are so widespread nowadays that they can be bought from sandwich retailers of all stripes, as well as from cafés and canteens across the land. Naturally, it is not just the waitress on the Holloway Road who gets the grammar wrong. There is, of course, no hard-and-fast rule on how to form plurals with foreign words in English; the process generally seems, like much else in the development of our language, rather random. We throw confetti, cook spaghetti, eat antipasti, and consume quantities of salami. This is nothing new. But now we also buy biscottis and order paninis whilst our coffee is prepared by baristas, thereby happily combining an existing Italian plural with a redundant English one in the first two cases, yet opting for the singular Italian noun in the third example – from the pedant's point of view, this latter formation being the sole one that is acceptable (and indeed, other Italian words with –a endings seem to attract the use of plural –s endings when adopted in English, e.g. ciabattas and foccaccias).

The logic of linguistic loans should, however, be sought elsewhere. Is it really surprising that most people who choose to eat panini are unaware of its singular form when the team that generated the publicity material for one of Britain's leading Italian coffee outlets is oblivious to such questions? Advertising its ‘All Day Breakfast Panini’, Caffè Nero describes this meal as ‘Free range egg mayonnaise with Lincolnshire sausage, bacon and tomato on a stonebaked panini’ (emphasis added).

The same outlet offers a further alternative to the common-or-garden sandwich in the form of tostati, a clever coinage that does not require translating as it sounds so similar to the English toasted. This is a term that fits the bill in more ways than one: it unites the need for translinguistic transparency with the deep-seated certainty that the Italian language – at least in the case of comestibles – is not very different from English. All you need to do, such terms reassure the majority of unreconstructed monoglots, is add an –i ending to form an Italian-sounding word (in other areas, try adding an –o or an –a) and, hey presto, you don't have to shout any louder… what's all the fuss about foreign lingos anyway?

If it is easy enough to get across the concept of ‘tostati’, its derivation needs unpicking. First, a point of grammatical order: the word cannot be used as a noun in Italian. It is a past participle and therefore functions as a modifier. Although the collocation pane tostato [toasted bread] is found often enough, the most frequent use of tostato is to mean ‘roasted’ rather than ‘toasted’, as in caffè tostato [roasted coffee] or pinoli tostati [roasted pine nuts]. Now, the most important thing to remember here is that if you happen to be in Italy and want to order a toasted sandwich in a café, you need to ask for a toast (un toast), pronounced with a suitably local accent. Geddit? Indeed, this long-established snack was Italianised as far back as the eighteenth century, so that the word tosto (which normally means something quite different) preceded toast, a usage that curiously is not all that dissimilar to the British tostato. Evidently, Italians have been equally guilty of using English words erroneously or out of context, as we are of misappropriating their lexis, when not busy minting the odd counterfeit coin.

At any rate, this particular Caffè Nero culinary concoction comes with the reassurance that ‘Our Tostati is a smaller lighter eat than our panini, made using slices of ciabatta bread […]’. No one could fault the company on grounds of grammatical consistency though, having established the notion of an -i ending as singular, the copy-writer has simply ploughed ahead, pluralising where necessary according to native custom. Contemporary usage in English seems increasingly to favour this way of forming the plurals of Italian masculine nouns, e.g. crostinis, and not infrequently, amarettis (in the US courgettes are referred to by the Italian term, which also produces a pleonastic plural; thus: zucchinis). By way of comparison, it is worth looking across the pond. There, an American firm calling itself ‘Anita's Biscotti’ supplies what are described as ‘homemade, gourmet Italian specialty biscotti cookies made in the USA’, promising in proverbial Anglo-American style: ‘A Biscotti a Day Keeps the Sweet Tooth at Bay’.

That which is most prized about Italian food can perhaps be summed up in the notion of a gastronomy rooted in tradition – the subject of countless television programmes – and based upon old-fashioned, ‘authentic’ ingredients, containing no food additives, replete with health-giving properties that combat cholesterol and heart disease; their miraculous effects, including longevity, revealed regularly in newspaper articles and celebrated on the cookery pages of magazines. Nothing comes closer to our desire for an affordable elixir than olive oil. The salad dressing of choice, intended to be drizzled over a few rocket leaves in would-be trendy eateries, as well as in homes the length and breadth of Britain, is that essential (Italian) extra-virgin olive oil which is used to transform an unprepossessing piece of mozzarella into an appetising Mediterranean starter, with the sole aid of a few slices of tomato and some basil. These days olive oil is also used to sauté not only onions and mushrooms but courgettes, peppers, aubergines and butternut squash where once a less colourful assortment of vegetables would have been boiled, or fried in an indeterminate and undisclosed cooking oil.

Such is our belief in the improving qualities of olive oil that it is introduced everywhere, including in bread. Thus, the now-ubiquitous ciabatta (the word's first meaning in Italian is ‘slipper’) becomes a slightly more sophisticated loaf when it is supplemented with a golden green liquid. Although in Italy this is not one of its ingredients, people expect to find the loaf made with extra virgin oil, seemingly its main selling point, to be found emblazoned on the cellophane wrapping of supermarket-bought and British-made ciabatta. Something has most definitely been added in translation.

No discussion of Italian culinary imports would be complete without mentioning ice cream, a long-established favourite in this country, adopted and variously adapted to suit different tastes since Carlo Gatti introduced Londoners to the frozen foodstuff in 1850. This didn't prevent a journalist, only a few years ago, from reporting breathlessly on a trend she had spotted; the headline for her article announced: ‘Gelatis are the new ice cream’ (Metro, 21 July 2009). Rebranded it may be, but grammar now appears superfluous to its needs: we simply know what this object is, irrespective of whether it is referred to as gelato, gelati, gelati's (and occasionally gelatis) in either or both the singular or the plural.

So, if Italian words such as pizza, pasta and pesto have enlivened our language (as well as our taste buds) and have become, for many in the food business, their bread and, er, olive oil, who really cares if the more recent arrivals of biscotti, panini and tostati are mangled in their transferred meaning and grammatical endings? Just carve out a small place for yourself at a pavement table, hopefully with something resembling the sun overhead, and enjoy the aroma of freshly ground coffee (which should temporarily mask other urban odours). Oh, and please do not forget to dunk your biscottis in the oversized cup of cappuccino which will probably also come in useful for warming your hands. Buon appetito.