[QUOTE=Kythereia]
Can I just say that from the heart of my first-year linguistics class, I swoon at thee? 
How do you account for the click consonant? has always been curious about this
[/QUOTE]
Yay!!! I always love to see new people getting interested in linguistics! 
Now, time to learn about clicks! To begin with, as you probably remember from your introduction to phonetics, when we classify a consonant there are five aspects that we tend to keep track of. What are they? (test yourself before you read on!) Typically, phoneticians will classify a phoneme based on: airstream mechanism, phonation type (voiced/voiceless), place of articulation, oral/nasal, , and manner of articulation. So an ordinary /b/ sound would be a pulmonic egressive bilabial oral voiced plosive (or stop). Oral/nasal is annoyingly redundant, so we usually leave that out in casual conversation and assume that if nobody says anything, it’s oral and not nasal. Airstream mechanism is the same way, in that if we don’t say anything, people assume it’s pulmonic aggressive. Since you’re ignoring these two, you end up falling into the three-part Voicing Manner Place method of classifying sounds.
Now, back to clicks. A click is simply a stop that has two points of closure within the oral cavity. Since both stops will be sealed at the same time, you’ll have a small pocket of air trapped between them. You then proceed to rarefy the air pocket by pulling the tongue back in a sort of sucking action. This results in the frontmost of the two closures being released while the rear closure is still sealed, which results in extremely loud plosion which seems to originate from the forward cavity.
Now, I’m oversimplifying a lot, and in the field you’re going to find that some clicks sound like clean stops, some will sound more like affricates or fricatives, and in the worst cases you’ll find languages whose clicks sound really, really close to ejectives.
In any case, now we can look at the big thing that makes a click a click: the airstream mechanism. As you’ve no doubt deduced, the source of phonation for a click can’t be the glottis, since a rear closure is in place during articulation. Air is going to be sucked in, due to the tongue action, and it will immediately blow out again, creating the noise. Now if an egressive sound involves air being pushed out through the glottis and through the oronasal cavity, then what would you guess air being sucked in would be called? Yep, you would call it ingressive! So we know that we’re looking at an ingressive airstream, but you’ll remember that when I defined an ordinary /b/ sound I used two words to describe the airstream: in particular, I called it *pulmonic *egressive. Pulmonic is just a fancy-ass way of saying “lungs”, so it’s acting like an airstream place of articulation, describing where the sound source is. So for the second part of the airstream description, we need to look at the individual stop to see where the rearmost closure is. The dental click, for instance, which tends to be the most common type of click found in the world’s languages (and even then, we’ve only definitively documented it in some African languages and in the Australian Damin ritual language), has closures at two points: the frontmost closure is at or just behind the teeth, and the rearmost closure is at the velum (which is very common for clicks). So with the place of rear closure being located at the velum, and with the manner of phonation being drawing air inwards, how would you classify the airstream mechanism of the dental click? If you said velaric ingressive, you’re correct!
So let’s review: clicks are a lot like stops in the way they’re articulated, only instead of a single closure they always have two coinciding closures. The frontmost closure is released first, by the tongue drawing back in a sucking motion, and this motion, along with the bernoulli effect, pulls air in, and immediately forces it back out, creating the actual noise. Therefore clicks are ingressive sounds, but unlike most ingressives, for which the airstream mechanism is actually pulmonic ingressive (pulmonic because air is being pulled into the lungs, instead of stopping at a velar closure like most clicks do, ingressive because the air is going in), these sounds are actually velaric ingressives. If you want to try visualizing the difference, the airstream in a pulmonic ingressive travels in a sideways L shape: it comes straight into the mouth, hits the back of the throat, and then drops straight down into the lungs. A velaric ingressive, however, is more like a C: air comes in, hits the velar closure, curves up or down, and gets pushed right back out.
And that is that! Was that clear-ish? If you have any other questions, I’d encourage you to ask; linguistics is important to learn, and I think people’d enjoy hearing about the kind of stuff your program focuses on. 