The protoss are telepaths, presumably the listener hears in whatever language they know. Note, however, that they do have a language of sorts, that can be both written and telepathically "vocalized".
The zerg, being a hive-mind, have no need for language. Only the rare sentient Infested Terrans have been known to occasionally communicate with other species. The Primal Zerg in Heart of the Swarm have no problem communicating with their distant cousins (despite lacking a hive mind), but are never shown communicating with Terrans, so it's not quite clear what is happening there.
Protoss do Class 6 type to get rid of the zerg. The planet is covered with plasma and magma when they're done. Nothing gonna be living in that mess. Somehow, the Zerg still do.
Terrans also demonstrated a capacity to do this, by launching numerous nukes from orbit and reducing the surface of the planet to a black glassy substance. This led to the outlawing the manufacturing of full-size nukes to prevent such an event occurring again, leading to the multiplayer usage of "mini-nukes" that inflict underwhelming damage at relatively cheap cost.
Army of Thieves and Whores: About fifty percent of the Terran armed forces are criminals who have undergone biochemical resocialization (read: brainwashing). These criminals range from the usual suspects (murderers, thieves, rapists, etc.) to the occasional political prisoner.
The Protoss believe that they ascend into the Khala when they die, which treated like some kind of a gestalt consciousness uniting the entire Protoss race. They believe that particularly powerful or influential individuals linger on long afterwards. This was so proven in the case of Tassadar, who was not completely obliterated by his kamikaze attack on the Overmind.
As You Know: During the Terran 7 mission briefing, Kerrigan explains the origin of Terran Ghosts to Raynor and Mengsk, even though both characters have had quite a bit of experience with them already (Raynor losing a son to the Ghost program, and Mengsk having Kerrigan, a Ghost herself, as his second-in-command and the one who killed his father).
Base on Wheels: One of the major Terran advantages. Their command base and primary production facilities are all capable of being lifted up off the ground and moved to other locations, either if there's an imminent enemy attack or if they just need to move to an area with better resources. Technically they don't roll on the ground as per standard for this trope, but they're not able to be used as bases until they touch down, and their movement speed is pretty slow.
Big Bad: At first it seems to be the Overmind, then Kerrigan. It's not. It's actually The Dark Voice aka Amon, a vengeful Xel'Naga who tried to destroy and recreate all life in the universe in a fit of pride and jealousy and was put down by the other Xel'Naga for it.
Brainwashed and Crazy: The Zerg were forcibly changed from a race of peaceful worms low on their world's food chain to the Assimilation Plot driven Horde of Alien Locusts with Psychic Powers we all know and love by the Xel'naga and the Dark Voice. Note that some strains of Zerg are actually derived from various species that the Swarm encountered and consumed throughout the Galaxy. The Hydralisks were once the herbivorous Slothien herd animals, the Mutalisks were Mantis Screamers, and the Behemoths (likely now Leviathans) used to be peaceful Space Whales.
Subverted by the Overlords whose host species willingly offered themselves up for infestation to avert their oncoming extinction through starvation.
Convection Schmonvection: Magma tiles in the Ashworld tileset (e.g. Char) act exactly like water tiles on any other tileset, and no units take damage from being nearby. This may be justified though: the Terrans are all either in vehicles or wearing Powered Armor (which we know can survive hard vacuum, so being heat-resistant isn't much of a stretch), the Protoss have shields and probably other applicable phlebotinum, and the Zerg originally evolved on a similar planet.
Crapsack Universe: The individual factions all suck one way or the other, the only genuinely nice, trustworthy people are the individuals with no real power.
Terrans act somewhat like locusts, moving from world to world to drain the resources and most of their standing military consists of mind-controlled convicts. Of their governments, the Confederacy was corrupt to its core, the Dominion is slightly better but compensates with its Emperor's extreme narcissism, and the UED are Space Nazis. The lesser governments are the Kel-Morian Combine and the Umojan Protectorate. The Kel-Morian Combine has been compared to a massive criminal organization, and is said to practice slavery. The Umojan Protecorate is apparently the only good government, but it is generally weaker and less populous than either the Combine or the Confederacy/Dominion, but evens the odds with extremely potent technology and a huge spy network.
The Zerg want to achieve perfection... by absorbing every other being they encounter, until they're the only race left.
Critical Existence Failure: Units and buildings will be perfectly fine so long as they have any health, though Zerg and Protoss buildings will show damage. The only exceptions are Terran buildings: if their damage meter dips into the red range, they'll catch on fire and start taking damage even if they're no longer being attacked. But if SCVs repair them back into at least the yellow health range, they'll be perfectly fine and functional.
Crystal Spires and Togas: The Protoss are a near-literal example. Khaydarin crystals are featured heavily in their architecture due to them acting as a conduit for psionic energy, and out of battle the Protoss wear simple cloth garments like loincloths, cloaks and capes.
Cutscene: Of the Blizzard cinematic variety. They've only gotten better and better over the years. Starcraft II also uses the game engine for some pretty high-end cutscenes, that are only inches below the actual cinematics.
Damage Is Fire: Terran and Protoss buildings burn. Zerg buildings bleed. Terran buildings on fire take further damage from it until it's destroyed or sufficently repaired. The heaviest the damage, the more widespread the fire/blood.
Deflector Shields: Personal type. Every protoss unit has them. In some of the games, some Terran units can create a Defensive Matrix for friendly units or create their own.
Doomed by Canon: One of the novels "I, Mengsk," goes into the details of Arcturus Mengsk's past, including his homeworld of Korhal and his family. People who are familar with the story of the games know what happens to Korhal and the Mengsk clan.
Also, Ulrezaj in his archon form and their boss, The Dark Voice.
The Overmind might also count.
Energy Ball: Numerous units can fire these out, most notably the Protoss phase disruptors, used by photon cannons and most of their vehicles.
Evil Counterpart: The Zerg were deliberately engineered by the Xel'Naga to be an opposite of the Protoss as part of their experiments. The Protoss have "purity of form" while the Zerg have "purity of essence." The Protoss use a telepathic link that connects all of them, the Zerg are a Hive Mind. The Protoss are graceful and intelligent, the Zerg are bestial and driven by instinct. Even in battle they use opposite techniques, the Protoss army consisting of singular elite soldiers who have spent years training forwar, against the Zerg army consisting of lots and lots of expendable units evolved to be killing machines, and little else.
Of course, this is only a superficial interpretation. The Dark Templar novels reveal that the "Turned Against Their Masters" gig is a Protoss fabrication. The Zerg and Protoss were created in order to unite with each other and create a new iteration of the Xel'Naga (it's just how those guys worked) as part of their life-cycle. The Zerg got corrupted by an Eldritch Abomination before that could happen, however, and were made to attack their makers and the Protoss.
Evil Is Visceral: Aspects of the Zerg that do not fit neatly into other tropes: the way that buildings pulsate when they are being constructed, their sound effects (especially if liquids are involved), the Overmind's influence is represented by a big eye. Then there's the growing tissue sample in Starcraft II...
Evil Versus Evil: Most of the conflicts that Arcturus Mengsk is evolved in - he starts in a kind of Black and Grey Morality situation against the Confederacy, and once he gains power falls into a neat Evil Overlord niche, but the fact that genocidal aliens and imperialistic Earthlings are a greater threat means he's constantly able to fight them and portray himself and the Dominion as heroes.
Terrans are Balanced. They have all the Long Range Fighters, with only one melee unit (the Firebat) and the unit with the longest firing range (the Siege Tank), but their units tend to be Glass Cannons in compensation. They have the best standing defenses in the form of Bunkers, which you can hide infantry in, and some of their buildings can take off and fly to other locations, but at the cost of subverted Critical Existence Failure: Damage Is Fire, and if a Terran building's Life Meter is reduced far enough, it will burn down of their own accord unless repaired. Finally, the Terran military is less mobile as a whole; their units are Master of None, they need to rely on each other for support, and they have to either leave some units at home or leave their base undefended.
Zerg are Subversive, with lots of small, fast, weak units suitable for a Zerg Rush, all the Suicide Attackers, and lots of Body Horror, Hollywood Acid and Combat Tentacles. Their Worker Units don't so much build structures as mutate into them (consuming the Worker in the process), and many of their powerful units have to mutate out of a pre-existing lower-tier unit. Their structures must be built on "Creep," which is generated naturally from their central Hatcheries and blocks the other two races from placing building. Zerg have Regenerating Health and will heal From a Single Cell. Where a few Terran and Protoss units have Invisibility Cloaks, almost all Zerg ground units can "burrow" underground, allowing them to ambush, recon and heal. Finally, because of the way Zerg build unitsnote The other two races can only build one unit at a time from their production facilities, and each facility is limited to a single style of unit: barracks can't make airplanes, for instance, and airports can't make soldiers. Any Zerg Hatchery can build any type of unit currently available, three at a time, they can generate new armies at an instant, in case there's been a Total Party Kill or you've found some Tactical Rock-Paper-Scissors to exploit, but their Tech Tree is also markedly more vulnerable to destruction.
It's also interesting to compare each faction's basic units. Terrans have the Marine, who has has the lowest Hit Points of the lotnote 40 in SC 1, 45 in SC 2 with an upgrade to give them 10 more, but carries a gun against the other units' melee attacks. The Zergling is a four-legged beast, with the fastest movespeed of the three units and an upgrade to make it faster, and is so cheap that Zerg players get two of them for the cost of one Marinenote with 35 HP each, for a total of 70. Finally, Protoss have the Zealot, who has the most HPnote 100 HP, 60 shields and does the most damage per attack, but costs twice the resources, twice the Supply points, and takes up twice the room aboard a dropship.
Fantastic Rank System: The Protoss have a different rank structure, though only three ranks are ever mentioned in the original game:
Praetor: Probably close to an Army Captain, Fenix held this rank, as did Artanis in Brood War.
Executor: Probably close to a Brigadier (1-star) General; Tassadar, Artanis, and Selendis held this rank. The High Executor leads the caste.
Judicator: A high-ranking government official, Aldaris held this rank.
Prelate: The Dark Templar equivalent of Praetor. Zeratul was addressed as such in Brood War.
Starcraft II introduces cosmetic ranks for any standard unit based on number of kills. For Protoss, 0-4 kills is a Disciple, 5-9 is a Mentor, 10-14 an Instructor, 15-19 a Master, and 20+ an Executor. Zerg equivalents are Predator, Slayer, Ravager Assassin and Metamorph, and while hardly fantastic, for the sake of completion, Terran get Recruit, Corporal, Sergeant, Captain, Commander.
The Protoss and Terrans have FTL Warp drives, while the Zerg Overmind can use its massivePsychic Powers to tear warp rifts in spacetime.
Protoss have near-instantaneous precision warps, to the point that their buildings, infantry and ships are not "built" but are warped in from their homeworld or automated factories. Protoss soldiers even have armor that teleports them out when they are gravely wounded in battle.
The arrival of the Terrans in Koprulu was actually a navigational accident. The flight computers on their sleeper FTL ships malfunctioned, and overshot their destination, travelling at FTL speeds for about 30 years (adding up to some 60,000 light-years from Earth). Over time, the Earth Directorate has managed to advance FTL technology to allow them to get to the Koprulu Sector from Earth in a matter of months.
Future Slang: The novels introduce "fekk" as a curse word. Of course, 'feck' is contemporary British slang.
Gambit Pileup: The entire storyline. Every major character in this game, human or otherwise, seems to have some sort of hidden agenda and it's nigh-impossible to tell who's getting the upper hand. Mostly, it doesn't work out well for anybody.
Genocide Backfire: The Terrans in the Koprulu sector were descendants of unwanted people on Earth who were sent on hardly inhabitable places to test if they could survive. They can. It should be noted that the genocide might not have backfired if the sleeper ships hadn't missed their destinations.
Hammerspace: Terrans have building components appear and snap themselves together out of thin air.
Hive Mind: The zerg Swarm, obviously. The Khala of the protoss is also somewhat like this, only the protoss in the Khala retain their individuality and free will, and can choose not to share all of their thoughts and feelings with others.
Hollywood Acid: Often used as a weapon by the Zerg. And now there is a Starcraft II short story called "Acid Burns".
Hufflepuff House: Both the Kel-Morian Combine and the Umojan Protectorate get no screentime in the original game, beyond a blurb in the manual. The Combine was later elaborated on in Brood War, but Umoja only makes a small appearance in the prologue of Heart of the Swarm.
Humans Are Divided: Humans are the most divided of the three races by far, with every game having a war between two or more of their factions.
Humans Are Special: Deconstructed. The Terrans of the Koprulu Sector are only a few generations away from becoming a psionic species. Instead of indicating that humanity is on the verge of becoming something greater, this just means they drew the attention of the Zerg, who view their psionic potential as the key to fighting their real target, the Protoss, on equal grounds. Interestingly, Humans are the only major race that was not created/uplifted by the Xel'Naga.
Humans by Any Other Name: For all intents and purposes the term "Terran" is used as a substitute, both by humans and by non-humans, for the word human. This is particularly odd since Earth (except for in the expansion) is practically a non-factor and the word Protoss has nothing at all to do with the name of the protoss homeworld (Aiur). As for the Zerg, it's unclear if they're named after Zerus (given the unusual spelling) or whether Zerus is named after them.
Humans in the series are considered flawed, weak, violent, and greedy by the Protoss and Zerg. Outside of Raynor's alliances with the Protoss, the humans are prone to civil wars and in-fighting even as they flee/fight the Zerg and Protoss. The climax of StarCraft II: Wings of Liberty, when Raynor and the Dominion invade Char and de-infest Kerrigan is pretty much the only heroic thing the race has done in the grand scheme of things.
Also in Wings of Liberty, Jim Raynor is shown a vision of a possible future where the Terrans and Protoss are driven to extinction by the zerg/protoss hybrids in a timeline where Kerrigan dies, and can't lead the Zerg swarm.
Then again, humans have been shown to at least be better at fighting the zerg than the Protoss in the games making this a possible subversion. Raynor played a major part in the defeat of the first overmind on Aiur, the United Earth Directorate seized control of the second in brood war, and humans took one of the zerg's best defended worlds, char twice. Let's also not forget that Sarah Kerrigan, the Zerg's current leader is a former human.
Hybrid Power: The protoss and zerg were both uplifted by the Xel'Naga to have "purity of form" and "of essence", respectively. The program to hybridise them theoretically creates the Ultimate Life Form.
Instant-Win Condition: In the multiplayer; you win the game if you destroy every building the enemy player controls, even if your own base is in shambles and you're on your last unit. There is a reason for this: During the beta for the first game, a very common dirty trick was for a losing player to hide a very difficult to spot building such as a supply building in an obscure part of the map in hopes that the opponent would give up and cede the game in frustration.
It's the Only Way to Be Sure: Protoss policy on planets that have become too infested with Zerg to be saved is to glass the entire planet from orbit. It's a last resort and its main use is to make sure that even if a planet is lost, the Zerg will at least not gain another foothold. Some of the problems in the first game come about because Tassadar decided to be merciful and let some of the Terrans escape, which let the Zerg do the same.
Late Arrival Spoiler: Woe to any who has no existing knowledge of the series, as Sarah Kerrigan becoming the Queen of Blades was a major spoiler in the middle of the original game's campaign, but it is now common knowledge since the game in question was released in 1998.
Mental Fusion: The Khala, the basis of the Protoss religion and integral part of their identity, is a form of this. Protoss are universally psychic, and evolved a super-powerful collective consciousness that manifests as magic-like abilities. Communion with this "Khala" is actually touching all the minds, thoughts, and emotions of the Protoss race at large. Unlike some forms of fusion, however, the communion with the Khala is expected rather than completely voluntary, and opponents are seen as heretics: there is a small group of protoss who fear that this will, one day, completely subsume their personalities, and take steps to sever themselves from it permanently (they evolved their own culture).
The first game's high templars can perform a one-way fusion into an archon, a ghostly psionic entity that is very damaging and quite hard to kill* barring use of the science bessel's EMP, which strips their shields to leave them with just a small amount of HP. Brood War allows two dark templar to fuse into a dark archon, a caster unit.
StarCraft II dispenses with the dark archon, allowing archons (initially called twilight archons, but this was dropped in early patches) to be created from any combination of two high templar or dark templar.
Messianic Archetype: Khas, Adun, and Tassadar for the protoss. The first was the originator of the Khala, which brought an end to their tribal warfare period and unified them as a single race. The second refused to exterminate the dark templar on orders of the Conclave and eventually sacrificed himself to protect them. The third sacrificed himself to kill the Overmind and save Aiur. Or did he?
Mobile Factory: All Terran structures capable of producing units are mobile.
Neglectful Precursor: Early on, it's revealed that the Xel'Naga were trying to create a perfect race: The Protoss were a failed experiment, but they succeeded with the Zerg, up until the point where they got eaten.
In the Dark Templar novels, however, it's revealed that the Xel'Naga were done with the Protoss; they had completed their work and left to create the Zerg as a complementary species, which would have, in time, joined with the Protoss to create the Xel'Naga's descendants. Someone screwed that gig up, though.
Raynor, and the Player Character, help Mengsk defeat the Confederacy; only for Mengsk to prove himself to be just as bad as the Confederacy and proclaim himself Emperor.
In the end of the Protoss campaign in Brood War, the Protoss acknowledge that by using that Xel'Naga temple to destroy the Zerg on Shakuras they will greatly weaken Daggoth's forces, which in turn will help Kerrigan. They also state though that doing so is the only way that they will survive.
Zeratul's killing of Zasz was the first time a Cerebrate actually died, but it also linked his mind with the Overmind and revealed the location of Auir. Zeratul later killed the second Overmind ending the UED's control of the Zerg, which meant that Kerrigan then had complete control of all the Zerg.
Nothing Is Scarier: A retroactive Type 1 example: One complaint about the Hybrids in Starcraft II is that they aren't nearly as frightening in that game as they were in Starcraft I; and one reason why they were so scary in Starcraft I is that almost nothing was known about them.
Optional Stealth: All three races offer a substantial variety of units, so you can employ a Zerg Rush, use stealthy tactics or More Dakka. For example, in the final mission in the original game, the nominal strategy is to wage a war of attrition using stealth as a secondary tactic, but a more spectacular and equally effective (though more costly) method is to simply build a massive force for an all - or - nothing battle.
The uniforms worn by United Earth Directorate officers resemble Nazi uniforms, right down to the grey overcoats and hats. Oddly, their bosses are a Frenchman and a Russian.
The UED gets bonus points for using the same interior decorators as Nazi Germany. Both have red flags with similar symbolism; the UED shows an eagle atop the Earth, echoing the Third Reich's eagle atop the swastika.
How about their predecessor, the United Powers League, who rounded up all cyborgs, mutants, punks and "undesirables" from Earth and either killed them of shot them off into space?
Regenerating Shield, Static Health: The Protoss faction. In contrast the Zerg regenerate health slowly while the Terrans have units that can restore the health of others, and neither faction has shields.
The Remnant: The Confederacy just won't seem to go away after being defeated by Mengsk. The UED still has pockets of forces left behind in the sector. Groups of both go to work as mercenaries. The novels also mention other rebel groups that fought the Confederacy separately...and then went right on to fight the Dominion, since it wasn't any improvement.
The Republic: The Umojan Protectorate, which of all the major Terran states seems to be the only one that's consistently "good".
Justified for the Protoss, who warp in their structures and units already constructed from somewhere else.
Justified for the Terrans; all their buildings are prefabricated, and Starcraft II's better animations show that the SCV is operating an assembly armature that is included in the building kit, rather than welding the whole thing together by hand.
Schedule Slip: Anytime Blizzard issues a release date for a full game.
The novel Starcraft: Ghost: Spectres has been delayed so long and for so many times, it's aping the Vapor Ware game it's based on.
Sci-Fi Writers Have No Sense of Scale: When the Terrans first arrived to the Koprulu sector, they only numbered approximately 32,000. According to Blizzard's website, there are at least twelve billion Terrans in the Koprulu sector at the beginning of Starcraft II, and Raynor mentions Kerrigan killing eight billion people during the first game. He might have been including the Protoss but that still means you're looking at more than twelve billion humans living in the sector. As mentioned here, to have this many people after only 240 years would require the population to at least double every decade, for 24 decades, not taking into account the deaths that occur from any number of natural and unnatural causes, because the Terrans have a history of civil wars.
Sequel Hook: Dark Origin. Which is notable due to the level being a unlockable secret. Unless you finished the previous mission within a certain amount of time, and haven't cheated, the player would never learn about the plot.
Shoot The Shaggy Dog Story: By the end of Brood War, the Confederacy was replaced by the equally rotten Terran Dominion, which was then devastated by the UED and Kerrigan. The Zerg invaded Auir, were stopped, but killed virtually the whole population first. The Protoss evacuated to Shakuras, but were still devastated and lost their leaders. The UED conquered the sector, but were defeated and wiped out by Kerrigan. The Zerg created a second Overmind (virtually undoing Tassadar's sacrifice), which was then killed. In the end, Kerrigan is the ruler of the sector, and the heroes have been defeated in virtually every way.
Sleeper Starship: The original Koprulu sector colonists were loaded onto a bunch of ships with experimental warp drives in cryo and spent thirty years in warp due to a computer error. The UED Expeditionary force used cryo as well though they made the trip in less than one year.
Sliding Scale of Idealism vs. Cynicism: The first game is somewhere in the middle but leans more towards the idealistic side. Brood War abruptly veers to the cynical side and keeps going until it becomes downright depressing. StarCraft II turns things back towards the idealistic side of things.
Whatever communications systems are used by Terrans work perfectly, no matter the terrain or distance. The closest it comes to Cell Phones Are Useless is in Brood War, where Duran claims Admiral Stukov's signal is breaking up, and that he can't see the Zerg swarms supposedly attacking the base, possibly due to a sensor malfunction. He is, of course, lying, as the player sees the Zerg attacking.
Suspiciously Small Army: Rampant, in quite a few missions your enemies have very small armies, or at least small armies that you see. The later missions have larger bases with more troops, but you're still not going to be seeing enemy forces number in the thousands like you would expect from an actual army.
Tactical Rock-Paper-Scissors: Exaggerated. In addition to some units only being able to hit airborne or ground-going enemies, the first game had damage types, which gained or lost effectiveness in percentages depending on the opposing unit's physical size (small vs large). The sequel added unit composition (biological vs armored) and replaced the percentages with specific, individual bonuses. And, always, lots of small cheap units can easily gang up on a large expensive one. The end result is a tangled web of counters, with each unit being specifically strong against one unit from each race, and being weak to one of each as well.
Themed Cursor: A sonar-like thing whose color changes depending on the alignment of whatever you're hovering it over. Green, yellow and red are friendly, neutral and enemies.
Turned Against Their Masters: Both the Protoss and the Zerg, against the Xel'Naga; the Protoss merely shooed them away from their world, while the Zerg killed most of them. The Protoss rebellion was just as violent as the Zerg's was. The only difference is the Zerg were all working towards assimilation of the Xel'Naga, and the Protoss were just killing anything that moved, including themselves. A good number of Xel'Naga were killed during the Protoss uprising.
Unobtainium: Neosteel, Khaydarin crystals and both Vespene Gas and "minerals".
Upgrade vs. Prototype Fight: The Frontline comics features a dogfight between a Viking, the Dominion's new experimental transforming gunship, and the Wyrm, the Viking's vastly inferior prototype.
Vestigial Empire: The Protoss empire, apparently even before the invasion of Aiur. It's implied this is because they've been fighting the Zerg for many years and are losing.
A Villain Named Zrg: To quote that page, "What four tropers out of five thought when seeing the title."
Walk It Off: Any Zerg unit or building slowly regenerates health. Protoss also slowly recharge their shields over time, which can make up between half to about ninty percent of their total effective health.
With Great Power Comes Great Insanity: Tends to happen to humans with high psi levels if not restrained quickly. The novels also provide this in device form, which blocks any attempts at mind reading at the cost of the user going slowly mental if it's used for more than a couple of hours. Which happens to both characters that had been using them for selfish reasons.
World of Badass: There are too many to count that even support units are this.
World of Ham: One way or the other, those who are not hams are easily numbered compared to those who are.