When terms in one language respond to a felt linguistic need in other language, then they are most acceptable. But when such words come in merely as a matter of fashion, of being fashionable, or being too lazy to reject them even though one is or should be well aware that there already exist, in one's native tongue, perfectly good equivalents, it is another matter.
René Etiemble was mocked, forty years ago, for his worries over "Franglais" but it was his mockers who deserve mockery. The fact that sometimes those who are involved in the Defense de la Langue Francaise may be a bit too rigid, or too humorless (and for that matter so have all linguistic purists, including those who, in writing English refused to use any but words of Anglo-Saxon origin, avoiding the Latinate element), does not mean that all objections to what has become the wholesale appropriation of foreign terms, is silly.
There are imports -- akin to that purple loosestrife that is not native to New England, but is now, in many habitats (including places where Thoreau once studied Nature), driving out native plants) -- that are not needed, and that do damage to the structure of the language. And while English can mostly take it, being famously flexible and receptive to linguistic imports, able to accommodate them better than languages with smaller lexicons, there are languages, such as French and Italian, where the over-borrowing is getting truly annoying.
One of the borrowings into present-day Italian that infuriates me is the English word "hinterland" which has gradually been driving out the perfectly good, long accepted, native Italian equivalent -- the word "entroterra." Then there is the linguistic contamination that one can observe in, for example, the employment of the word "determinato" in the English sense of "determined." Where once an Italian would describe someone as "una persona decisa" younger people might nowadays write, because of the English contamination, and a desire to be with-it, "e una persona molto determinata." Now "determinato" has, or at least had, another quite specific meaning in Italian: “una determinata situazione” means “a certain situation.” Now when such words as “hinterland” drive out the perfectly good Italian word “entroterra” and the English word “determined” is imported into Italy and simply confuses the natives in their own use of their own, already-existing adjective “determinato,” and even diminishes or dries out the use of the word “deciso” which is being replaced, in predicates, by the word “determinato” – this is not a situation that one need take lying down, or simply say, as some do, that this is inevitable “linguistic change” and there is nothing to be done about it, just lie back and, whatever you do, don't think of England. But of course one can oppose such developments, and the best usage can, if it is relentless and uncompromising, help to slow down or stop such moves (Admiral Shishkov may have been a figure of fun, but in the end, we are glad, are we not, that "vodopad" is the Russian word for "waterfall" -- and aren't we glad that the word "breakfast," modishly used by some French writers in the 1930s, never did replace that petit dejeuner), and linguistic protectionism is not always foolish, but both justified, and often successful.
It is easy to mock, especially in the Anglo-American world, those academies – the Académie Française, the Real Academia Espanola – part of whose task is to protect the language, and of course phrases such as “linguistic purity” merely invite ridicule and get backs up. But the role of English as this goddam world language is, in many ways, bad for other languages that allow themselves to be unduly – the adverb is important – anglicized, and bad for English itself, and for its native speakers, who see it being manhandled as the language of sports, entertainment, and business – with fewer and fewer being able to understand, much less emulate, the richest exploitation of the language and its resources.
Such things as this “hinterland” and “una persona determinata” in Italian are the linguistic equivalent of purple loosestrife that came from elsewhere, and is now in many habitats driving out our native plants and the fact that they simply substitute for perfectly good words in the non-English tongue, is troublesome. Words, or phrases, for which there is no real equivalent, words or phrases that add something to the language and can even be left, unmodified or scarcely modified, in the original language, might include "poshlust'" and "drucksache" and "cadeaux de rupture," to offer three examples that in the last day or two have appeared, and most appositely, at this English-language website.