How did the Protoss' "primal link" actually work across history?

[Mislagnissa]

Let's just ignore the SC2 retcons because they're nonsensical and only introduce problems because the writers didn't give a damn about common sense.

Mm, nope. All protoss are born part of the Communal Link, an unconscious empathic connection. It wasn't until Khas' research and development that a means of bringing that link to a conscious awareness took place. That is the Khala.

This is incorrect. There's no difference between the "communal link" as you call it and the Khala. Khas didn't create it, he rediscovered it. The original manual is explicit about this.

The original manual, vague as it is, states fairly clearly that the link is just a more efficient form of standard telepathy. The protoss' nerve cords act as antennas which increase their bandwidth compared to, say, humans. Where human telepathy is no more efficient than standard speech, protoss telepathy allows for them to communicate much more efficiently. (According to the "Project Blackstone" ARG fiction collected in the War Stories anthology, Zerg telepathy is mediated by special organelles that are also responsible for their innate gene splicing ability. Essentially, they exchange genetic information through telepathy.)

The manual is vague as to the degree the Khala was broken during the Aeon, but I am inclined to believe it still remained within tribes considering that protoss are happily willing to commit genocide otherwise.

Back in the Templar Census promotional site from 1998, the Terran scientist presenting the report (written from an in-universe POV) stated that the tribes had their own languages which they maintained for things like proverbs even though the empire used a common language. (The tribal languages were translated into Latin to provide the same feel to human readers.)

Based on that, I came up with some headcanon to explain how the breaking of the Khala actually felt to the protoss. Essentially, the Khala relies on a syntactic language just like any other form of communication (e.g. pheromones, computers, speech, bee dancing, etc), in this case the language of "Khalani". However, that isn't the only language among the protoss: every tribe had their own, which nowadays are about as archaic to them as Latin is to us. When the first Khala arose, this was due to the tribes adopting Khalani to share information. When the tribes broke, this was because they stopped speaking Khalani and started speaking in their tribal languages (whether restored from records or made up for nationalism). When Khas experimented with the crystals, he activated a translation program which translated the diverse tribal languages into a form he could understand (which was used to built the first Khala because that's easier than teaching everyone to learn a new language, and the program itself is a super-smart AI because that's the only way translation could work practically). Rebuilding the Khala was a matter of convincing other tribes to accept the translation software or something along those lines.

I don't like technobabble explanations and prefer to rely on actual explanations as much as possible. In this case, I think my language translation explanation makes more sense than anything else I could think of and makes the setting feel more believable since it uses real concepts like linguistics and computer science.

Logic dictates the Tal'Darim are born with the Communal Link, but evidence shows they either remove their nerve cords, or shield them off like Alarak. It's also possible that terrazine lessens their Communal Link. Or perhaps their Communal Link is so full of hatred and vitriol that it continues to fuel their aggression.

Supposedly they use sundrop. That's the explanation everyone else generally relies on when this comes up and they know enough about lore to recognize the retcons. The writers made them up as they went along so it's as good an explanation as anything else.

The idea that the link is so full of vitriol that it cancels itself out sounds iffy to me, but that is an original idea I would like to explore at some point. Insofar as the writers even understand how telepathy worked over the series (and they clearly don't), the intention seems to be that the tal'darim (and the protoss in their natural state) don't have any form of empathic communication. The moral of the SC2 story is that empathy is bad or something similarly stupid judging by how the characters treat the Khala's loss as something to be proud of rather than the beginning a new Aeon of Strife.

I'm in complete support of the Khala as a structure, since the protoss are contrived to be vicious warmongers as a species, and I think the Blizzard writers were fools who didn't understand it or care to. I'm in possession of common sense so I wondered how the dark templar were able to avoid falling into another Aeon of Strife without it, so I waived the problem away by claiming they use special meditation techniques like "The Flame & The Void" from Wheel of Time. The protoss refined psionics into a scientific field according to the lore so that sort of thing doesn't surprise me at all.

[Turalyon]

The Dark Templar retained an appreciation for individuality afforded by the Aeon of Strife, but none of the aggression.

Which is kinda BS when you think about it. Where/when did these proto-DT "lose this aggression" if they were never enlightened by the re-discovery and rejoining of their communal link? The "Khala" was the only reason the Aeon of Strife stopped, but that's because those that chose to be part of the Khala chose to stop fighting, not because the non-Khala adherents/proto-DT "lost their aggression". How did the DT become the idealised Randian representation of egoism when their closest ancestors were supposedly still "savages" (those who started and perpetuated the Aeon of Strife) who never saw/realised the "light" (of the Khala)? I can only guess as to why these proto-DT/non-Khala adherent Protoss became less aggressive: they probably cottoned on to the fact that the tide was turning against their way of thinking when the rest of the Protoss were becoming more communal and had to stick together to survive/preserve/maintain their right to individuality.

Every Khalai is a descendant as well then.

Yes, but the Khalai are descendant from a specific way of living that was vastly different from before. The DT are descendants from the Aeon of Strife, non-communal link adherent Protoss, in that they both have always held onto their individuality.

[Visions of Khas]

Hmm... now that we're on the topic, I wouldn't mind seeing how the Dark Templar transitioned from their Aeon of Strife/Khalai roots to the space wayfarers they became. There would be a lot of ideological development and possibly political intrigue. But that sort of diaspora story is too nuanced and complex for a Blizzard writer or any of their chosen authors to explore properly.

[Mislagnissa]

I didn't include research links in my last post, but here is an actual college lecture explaining why telepathy/empathy/etc would work on linguistic principles and exploring the applications in more detail.

http://personal.bgsu.edu/~swellsj/xe...telepathy.html

Long story short, if you take the concept seriously then telepathy is fraught with its own problems that must be addressed before you can use it practically. (The article doesn't address empathy, but it doesn't need to: empathy is the language of emotions.)