Apparently, the word 'mushroom' isn't taught in Swiss schools...
However, I, and most people I know, use the Italian name, porcini, when speaking English, as Boletus is a family name, and Steinpilz (porcini) is a specific type (Boletus edulis).
Tom
But yes, what newtoswitz is correct -- in the US or UK, these would almost certainly be referred to as porcino mushrooms or, less frequently, cepes. I've never seen the word boletus on an English-language menu, regardless of whether it's an English word or not...
"The name is derived from the Latin term bōlētus 'mushroom'"
Tom
Boletus is also a very specific species, with tubes rather than gills underneath, and very popular (and expensive- in Switzerland and Europe). As said above, Porcini in Italian, Steinpilz in German, and in France, 'Cep' in most of the country, but 'bolet' in the East- and also called 'bolet' in Romandie. They will be even more expensive now, as this season's was a bit of a disaster, and so few found, due to very dry Summer and Autumn.
The most used cooking mushroom is grown in caves on horse manure and straw- and is called 'champignon de Paris' (as it was first grown in caves in .. Paris)- and is much cheaper and less tasty. Unless you find the wild form 'rosé des prés' or other related species, which are much tastier.
I get really annoyed, as a mushroom buff- when restaurants advertise something cooked with 'wild mushrooms' when they clearly are not, but cave grown Oyster mushrooms and a darker form of 'champignon de Paris'.
If the canteen is advertising 'boletus' and serving 'ordinary mushroom' - then they are legally mis-representing. On the other hand- if you are truly getting 'boletus' then you are very lucky. I have complained many times when expected to pay good money in restaurants for 'wild mushrooms' and got ordinary mushrooms (strangely called 'champignons' in Germand, lol)...they were always very surprised, in the UK, that anyone knew the difference.
The only people likely to use "boletus" are naturalists and maybe chefs, and even then the latter wouldn't put it on their menu in most cases.
I mean, come on, in the USA, they call every meal "Swiss" that has some kind of a generic goo on or in it, although that stuff is not Swiss at all, maybe not even real cheese. But at least they tried. I would look at it as kind of poetic license (licence for the Brits) while trying to be nice.