Units and Buildings
Archon
More trivia than misuse, Archon derives from the Greek word ἄρχων, meaning ruler. Its plural can either be the Anglicized archons, or the rarely used but nevertheless awesome Hellenic arkhontes (ἄρχοντες).
Baneling
The centrifugal hooks upgrade can be pronounced as either "sen-trih-fyoo-guhl" or "sen-trih-fuh-guhl," the former being preferred in Commonwealth English, the latter in American English. Even though a related word, centrifuge, is pronounced "sen-tri-fyoozh" by both dialects, "sen-tri-fyoo-zhal" is incorrect. All these words take their name form a constructed Latin word meaning to flee the center, which is to say, rotate. Hence, the banelings spin around in circles after evolving their centrifugal hooks.
Colossus
It is traditional in English to maintain the Latinate plural in words derived from Latin, even if the word itself has origins other than Latin. Colossus, although ultimately derived from Greek kolossos (κολοσσός), entered English through Latin and is normally pluralized as colossi. Some forum users have suggested "colossodes" κολοσσοδες as a more authentic Greek plural, similar to how octopus (ὀκτώπους) can be pluralized as octopodes (ὀκτώποδες). The problem with this, however, is that ὀκτώπους is a third declension noun, whereas κολοσσός is a second declension noun. Therefore, following proper grammar, a more authentic plural of colossus would be colossoi (κολοσσοί), which would be pronounced "co-lo-see," similar to the Colosseum, a word with which it shares an etymology. Colossuses is an acceptable, if less common, English alternative with colossi being the preferred form.
Medivac
This is a bit of an error on Blizzard's part. The Rod of Asclepius is a symbol associated with the Greek god of healing, Asclepius. It is a staff encircled by a single snake, and because of its origins has come to symbolize medicine. The caduceus, on the other hand, is the staff of Hermes in Greek mythology. It features a winged rod entwined by two snakes. As Hermes was the patron, of, among other things, commerce, his staff was historically associated with commerce and exchange. However, in North America, errors made over a century ago have led to the Caduceus, not the Rod of Asclepius becoming known as the symbol for medicine, where it is often seen on ambulances, in hospitals, and on medical equipment. So, the intention of the upgrade name was to be a reference to the healing capabilities of the medivac, however, the game, being created by North Americans, ended up with a botched name due to a common misconception. The upgrade is pronounced "cuh-doo-see-us."
Nexus
Nexus is a Latin word meaning something which binds. It is a fourth declension noun, therefore its plural is nexus, not nexi. So, the phrase "both his nexus were sniped" is correct, but could lead to confusion amongst uneducated or nonnative speakers. Thus, the English plural nexuses is equally correct and generally preferred for the sake of clarity.
Overlord
Pneumatized carapace is pronounced "noo-ma-taizd." The Greek root pneuma means air, and pneumatized means to be filled with air, which evidently increases the speed of the overlord.
Queen
Larvae, the plural of larva, is pronounced "lar-vee." "Lar-vai" would be correct in classical Latin, but as it is a Neo Latin construction, "lar-vai" would generally be considered a hypercorrection.
Raven
Though rarely mispronounced, the corvid reactor upgrade often misunderstood. Corvus is the Latin word for Raven; corvids are members of the taxonomic family Corvidae, which includes birds such as crows and ravens.
Roach
The glial reconstitution upgrade can be correctly pronounced "glee-al" or "glai-al." Also known as neuroglia, glial cells are cells that take their name from the Greek word for glue, and act similarly, surrounding and assisting neurons in the nervous system. How reconstituting such cells would increase a roach's physical movement speed defies explanation.
Stalker
The simple past tense of blink is blinked. "Blunk," or worse yet, "blunked" are nonstandard.
Ultralisk
The chitinous plating upgrade is pronounced "kai-tin-us." Chitin is the sugar that makes up the shells of crustaceans, insects, and other arthropods.
Zealot
The first syllables of zealot, zealotry, and zealous, and zealousness all rhyme with the word gel. The second syllables are unstressed, rhyming with gut or pus. The word zeal rhymes with the word heel. Thusly, one could say that the "zel-uts" were attacking with great "zeel," but not that the "zee-lots" were attacking with great "zel."
Zerg
Zerg armor is correctly pronounced "cayr-uh-pays," not "cayr-uh-pus." Oddly, buildings have "building armor" instead of carapace.
Players
BRAT_OK
Pronounced "bra-tock," not "brat-oh-kay"
HasHe
Pronounced as "hash"
Idra
The first syllable rhymes with "lid," not "eye." The latter pronunciation was popularized by Artosis, who enjoys the power he gets from naming things.
KawaiiRice
Pronounced "Ka-why-ee," which means cute in Japanese.
Marine King
Prime is his team, Marine King is his ID. Keeping them together as Marine King Prime (MKP) is an awkward construction that could become confusing should he ever leave his team.
Sjow
Pronounced like "show," the j is similar in function to the j in fjord.
Socke
Socke is the German word for sock. In German, it is pronounced "zock-uh." "Sock-ee," "sock-uh," and "sock" are all incorrect, however the latter's usage could be justified as a translation.
xiaOt
Pronounced "Shee-ow Tee," with the first "ee" sound voiced only briefly. It means "Small T."