The bird (a thrush) conveyed the message from Bilbo about the weak spot in Smaug’s armor. It overheard Bilbo’s conversation with the Dwarves.
ETA: the name Smaug is pronounced correctly in the PJ movie. Check the LOTR appendices.
The thrush (the same one whose snail-knocking alerted them to the whereabouts of the keyhole) overheard Bilbo describing Smaug’s armour and its weak spot to the dwarves. They could not understand thrush-talk, but it understood them well enough, and Bard was miraculously gifted with understanding since he was a direct descendant of the lineage of Girion, Lord of Dale. So it arrived at the height of the battle just in time to tell Bard to wait for the light of the rising (sic - although it was a few days since the new moon on Durin’s Day) moon to illuminate the hollow of Smaug’s left breast, and the rest is history.
It’s been a while since I read the book, but I don’t remember the dwarves being archers. Did they just add in Kili/Fili as an archer so he can be the Legolas of the dwarves? If so, then in the book, the dwarves had literally no “shot” at killing Smaug, and only an archer could have. There’s also the whole distance & range thing… Dwarves always seemed to be a bit short-sighted to me, both in philosophy and tactics (“we’re wasted in cross-country… very deadly in the short sprint”). I mean, they had an entire kingdom of dwarves waiting behind the door when Smaug busted in, and they ALL HAD AXES. They could have had thousands of archers lined up in that hallway.
I am mistaken. After Siegfried tastes the dragon’s blood, he can understand the speech of the wood bird.
This has never happened before! I am not sure what to do…
Smay-og (or s-mow-g) depending on your accent, is more correct. The pronunciation was intended to be of ALL the letters involved - in other words, the A isn’t a silent modifier of the next letter after it, like it is in English, it’s supposed to be pronounced in its own right.
You may have noticed the same thing (or maybe not) with Sauron vs Saruman. In English, the first two syllables of those two are pretty much homonyms. Not in Tolkien’s intent. Sauron is intended to have the A and the U pronounced, leaving it more like “sour” than “sar.” To his mind and speech, the two sounded completely different from each other.
Unfortunately, I read the appendices AFTER I read the friggen Hobbit and LOTR, so I have the damnedest time getting the pronunciations right in my head, even though I know what they’re supposed to be.
This is just from the movies, not from any of the books.
And some of the dwarves in the books had bows: They used them to try (unsuccessfully) to hunt game in Mirkwood.
Well, they did bring down a squirrel, but it tasted so horrible that it was effectively inedible.
The hell do dwarves eat on a road trip, Chinese take out?
Cram. Basically hardtack.
I’m not here to defend Peter Jackson by any means, but this is justified in that the dwarves are to all reports the most capable among people of Middle Earth in withstanding dragon fire, as per The Silmarillion.
But one assumes they probably should have had archers as well.
In Tolkien’s universe, only a man (or a half-elf) can slay a dragon, besides a divine being.
Oh yes, matzoh. 
I wouldn’t say that only they can - just that, given our limited data set, that’s all we know who has.
It’s been a while since I’ve read the Hobbit, but aren’t the dwarves idiots? I seem to recall that most of the book is the dwarves dragging Bilbo, who’d much rather be home, getting in all sorts of trouble that he has to save them from, or, any time there’s something that seems hard or unpleasant, making him do it. They can’t kill the dragon because they’re not really able to walk and chew gum at the same time.
And what kind of movie would that be, if the Dwarves were something straight out of a cartoon? Especially after LotR?
Wouldn’t Dwarves be too small and stocky to wield an effective bow ?
In the movie, it was made quite clear that, aside from Thorin, Balin, and Dwalin, the company was anything but warriors. Certainly not action heroes.
Well, to be fair - it is Bilbo that wrote the book, of course he did all the real work.
I hear it tastes like a A ‘burglar-hobbit’
Exactly.
Balin: [after overhearing Bilbo tell Gandalf he will not join the Dwarves on their journey] It appears we have lost our burglar. Probably for the best. The odds were always against us. After all, what are we? Merchants, miners, tinkerers, toy-makers. Hardly the stuff of legend.
Thorin Oakenshield: There are a few warriors amongst us.
Balin: Old warriors.
Thorin Oakenshield: I would take each and every one of these Dwarves over an army from the Iron Hills. For when I called upon them, they answered. Loyalty. Honor. A willing heart… I can ask no more than that.
I always call him “smog” because that’s how my friend that got me into the books said it, how the cartoon said it, and because it sort of made sense that a fire breathing dragon might make some sort of pollution/smog.
I don’t care if it’s right or wrong, that’s what his name is to me.