Or so it is said. In fact, that is not quite true. The Acadamie Française - I think it's them - has been conducting a campaign to purify the French language by eradicating foreign words which have crept into everyday use; words such as "weekend" and "picnic" - although the latter is sometimes spelt "pique-nique", presumably in an attempt to make it look more French. I think the Acadamie is fighting a losing battle as those words are now far too deeply entrenched in the minds of the Frenchmen "sur la route".
There is another way in which that old saw is short of the truth. Sometimes the French don't have just a word for it; they have several. For example, a potato is pomme de terre, literally "apple of the earth", which is three words. I always thought the French for apple was simply pomme but I have recently seen the fruit described as pomme de l'air - four words, and literally "apple of the air".
But we Brits can't afford to poke fun at our nearest neighbours. After all, we no longer have an English word describing an establishment where one goes to buy a meal. We used to have chop houses, and then there were dining rooms, but they are now all called restaurants or bistros or cafes, all French words, although café in France means "coffee" rather than the place where one buys the drink. And it's not as though we are actually short of words in the English tongue. Take the words ditch, rill, stream, brook, dyke, burn and bourne. All of them mean a waterway smaller than a river, although it is true that they are not quite synonymous as there is an implied difference in the size of the waterway. That said, it is difficult, even impossible, to define just when a stream has grown big enough to be called a river, and some of those words are virtually obsolete or mainly regional in their use. One word missing from that list is creek. I think I'm right in saying that in America it is used to describe a waterway like a large stream or small river. In England that is not the case. Here a creek is a tidal inlet which may or may not lead to a stream and creeks are generally associated with areas of marsh.
Whether the words are French or not, what a vast wealth we have in our native tongue. Things can sparkle, glitter, glisten; water can be still, unmoving, limpid. It's such a shame that there are so few people nowadays able to use the language in the way that the Bard did 400 years ago. We are missing so much.