Do birds “sneeze” or its equivalent? Secondly, does one type of bird recognize the “language/song” of another bird?
Having been sneezed on (lots of water droplets abounding) by my cockatiel at home and a male American Kestrel at the rehab center, I can attest first hand that birds can expell irritants through the nasal passages.
I have seen the smaller owls at the rehab center (Screech-owls and Burrowing Owls) respectively freeze or dive into their burrows at the sound of a hawk calling overhead. They are in various enclosures with many types of non-releasable hawks nearby and are presumably used to their calls, but the sound of a ‘stranger’ hawk sends them into “I’m a tree branch/lump of leaves, you can’t see me!” mode.
Larger birds, when hunting, will zero in on the calls of smaller birds - a crow might recognize a blue jay and head on in for a meal.
Conversely, other birds recognize when one bird is trying to drive off a predator such as a hawk, a crow or a cat. One species, such as a Blue Jay, may sound the alarm and begin mobbing (attacking) the predator. Other species, including medium-sized birds (such as mockingbirds and cardinals) and smaller species (sparrows and warblers), recognize this alarm call and join in to drive off the intruder. [Safety in numbers, though I have seen a lone mockingbird harass a Red-tailed Hawk repeatedly and loudly.]
Just as humans build fences and dogs pee on objects, birds will establish their territories through songs. Most will ignore other bird songs, but will drive off those of the same species they hear in their own territory.
I defer to screech-owl for his great examples. I’d just add that the question is really too broad to answer, because birds vary enormously among species in their behaviors and abilities. But in general they have very good “language abilities.” At least one species of parrot has been demonstrated to learn the meaning of English words, e.g.
the first question was already answered, yes birds sneeze. and the second-- Many birds in africa have calls warning others of dangers that are near, and it has been vidoed (on discovery channel) of other specaies of birds (and mammals) reacting to this warning call, so yes birds can reconize other birds’ calls.
[sub]her examples[/sub]
oops. Sorry. i’m new 
Another interesting example is the Stellar’s Jay which does a fine imitation of a Red-Tailed Hawk. I’ve seen them scatter the compeitition with that one at semi-wild bird-feeders ( I’m thinking specifically of the one at Audobon Canyon Ranch ).
Also many passerine birds have geographic “dialects”. 'twas the specialty of my old Ornithology professor. I’ll quote briefly from his text:
Birds can recognize not only dialects but variations in songs of individual. This was clearly demonstrated by Falls (1969). On the territorial boundary of a White-throated Sparrow, he played tapes of the bird’s own song, its neighbor’s song, and the song of a stranger - all White-throats. The owner of the territory responded most vigorously ( in song-replies per minute )to the stranger’s song, about one-half as vigorously to the neighbor’s song, and between these two intensities to its own song. When the neighbor’s song was played on the “wrong” side of the experimental bird’s territory, the owner reacted as to a stranger’s song. This almost-human, xenophobic reaction of territory owners to strangers, has been demonstrated in at least nine passerine species ( Falls and Nichols, 1979 ).
- Tamerlane
Blackbirds have a metallic chip-chip-chip call which acts like a beware call on a predator, as if they were broadcasting the local news.
This is quite differant to the chattering fleeing immediate danger call and the response of other unrelated species is also differs with those calls, the ‘news broadcast’ causes them to hide but the ‘imminent danger’ call causes them to flee.