We don't say it every day but we've all said it at one point. It's another example of expressions commonly used when we have ZERO understanding why we're saying them. And that's totally right. English is an amazingly fluid tongue, quite different from the precise Greek or the martial Latin.
A language says a lot about the people who speak it. Know why Arabic is sparse in syllables? Cause if you keep your mouth open too long, the wind's gonna blow sand in it, that's why.
English is a nutty, idiosyncratic, grasping tongue, perfectly descriptive of the people who speak it. If a word will do service, we don't care what language we get it from. "Hammock" is one of few still known words from the now extinct Carib people. "Pajamas" comes to English via India.
Most of the phrases we English speakers regularly throw at one another? Most come from agriculture, navigation or warfare. That too describes us well.
"Don't look a gift horse in the mouth" that's agriculture.
Words like "ballast" or "rudder" and "anchor" are regularly used by those who've never been on a ship.
"Keep your powder dry" is of course warfare. Comes from a time when your very life might depend on the moisture content in your gunpowder. There was a time when readying a firearm for firing was an arduous task. For instance? West Virginia was largely settled by a curious collection of orphan brothers with the odd talent of being able to re-load muskets while in a dead run, with rather perturbed Indians about 50 feet behind them.
So we all know what "mealy mouthed" means, but why do we have that phrase in our lexicon? Well first, because it's useful. Second, the expression is about five centuries old. It means to hold meal in one's mouth, neither choosing to swallow nor expectorate said contents. It's the 16th century equivalent of one who'll neither defecate nor get off the pot.
William Shakespeare had the exact same understanding of the meaning of "mealy mouthed" as do people today wandering around Wal-Mart with carts full of Chinese made junk.
Martin Luther used "mealy mouthed" in some of his writings. And that's how language can unite across centuries. In some cases, I suppose it's possible the tongue defines the people, I've an open mind. (Hell, there are tumbleweeds blowing through my brain!) Every case I know of though, the people define the tongue. The French had a good head start on English speakers, but English speakers came here to farm. Being from an island nation, English speakers do enjoy ocean voyages. Warfare? History proves the heartfelt desire of all English speakers is to murder other English speakers, but we can work with surrogates! We're flexible!
We're a crazy race. Despite folk currently circumnavigating the globe to apologize for English speakers, I still think the world's a lot better off, in the margins. We're just crazy people with a stupid difficult language and we seldom think of the past, or even the present for that matter. Always pushing on to the future, that's the obsession of English speakers for some reason.
Well, as Kreskin said in opening sequence of "Plan 9" we should all be interested in the future, since that is the place we will live. (Page 138 in Dave's ever expanding unabridged compendium of DUH!) And it's not so bad walking around saying things you have NO idea why you say that stuff, but you know what you mean, and others do too. It's English. The crazy language of a crazy people who've contributed to the world, albeit perhaps reluctantly.
Personally Dave? I think you were rather "mealy mouthed" with this one.