Never trust the news...

...when it comes to etymology, anyway. The BBC has an article on the etymologies of several words or idioms that, it alleges, developed during the First World War. I'm habitually suspicious of such articles, and looked up the words I use. They were right on camouflage, but several others are incorrect, and quite badly so. The Oxford English Dictionary is not an infallible guide, but its citations put several of these words securely before the War:

1. "Dud," said by the BBC to have originally referred to a shell that did not explode and only later to have been expanded to other malfunctioning implements, already occurs in multiple broad usages in 1908. 

2. "Binge," which they allege to be a piece of Lancashire slang spread abroad during the war, was in use in both Northamptonshire, in the mid-19th century, and Oxford, by the end of the century. Neither is near Lancashire. Worse yet, the word was already used, as a verb, by Hilaire Belloc in 1910: surely a noteworthy enough writer that we could take it as already mainstream before the War.

3. For "crummy," they give an elaborate etymology linking it to lice, which resemble crumbs. The link with "lousy" is certainly present--in 1859. If it was "coined by American infantrymen" at all, they must have been pre-Civil War regulars. One wonders if it is really an extension of "crummy" meaning "strewed with crumbs," which is already in evidence in the 18th century. 

[On a side note, "crummy" was once a term of approbation for a pleasingly plump woman. Plumpness no longer gets the praise it once did, and I doubt your wife or girlfriend is going to want to hear, "Well, my dear, that dress makes you look remarkably crummy today!"]

4. "Cushy," we are told, was borrowed from Urdu; this is true enough (though the OED suggests Persian and not Hindi influence alongside Urdu), but again, the word is already cited in the 1890s. It might have been spread to the rest of the army by British Indiamen in WW1 (who knows?), but it certainly didn't enter English then.

5. The worst of all is another word of allegedly subcontinental origin. You or I might think that "chat" was related to "chatter," but no, the BBC treats us to an elaborate explanation of how it came from picking lice ("chats," in Hindi) off one's body while kibbitzing with one's fellow soldiers. The tale has the marks of an invented etymology about it--the suggestion of an exotic origin for a word of obvious etymology, the weirdly incongruous shift from literal to metaphorical meaning. And, in fact, it is completely made up: "chat" does mean "louse," but in English cant, and as early as 1699. "Chat" in various senses close to our own (though originally more negative) appears as a verb in the mid-15th century, and as a noun in More and Shakespeare! 

In sum: never repeat such stories, unless you've checked them yourself. They're too often wrong. I only wonder where the BBC people got their information (no citations, of course: always a bad sign, but typical in journalism; this earlier article, in a BBC publication, was more accurate). Several of these appear in Eric Partridge's A Dictionary of Slang and Unconventional English, but he notes the earlier appearances of "crummy," for example, and suggest that "dud" was merely "resuscitated" from relative obsolescence during the war. He also gives the "louse" etymology for "chat," but with no hint of the Hindi connection, and no suggestion that a connection with speaking did not exist beforehand. I'm guessing an intermediary, more popular, source.