I think it's a fun trope... but I also think it's only fun if you don't think about it too much. :D I have seen a few where some vague handwavery attempt at worldbuilding is involved (for instance, there was a fic which included a mention that having a soulmate outside one's geographic area was increasingly common, as travel times dropped/connectedness increased due to modern technology; I thought that was a nice little worldbuilding detail).
Aside from names or first words (and as others have said: HOW MANY people's first words to their soulmate would be something like "Hi" or "Welcome to McDonalds, can I take your order?"! Not at all helpful, and prone to lots and lots of false hopes being raised only to be broken.) I think the thing I've seen most is hand- or fingerprints, which does make more sense -- in the context of "literacy is not universal" -- than words do. And I've seen at least one fic which used symbols (somebody's characteristic weapon, e.g.) rather than words/names, too.
Oh, and there *is* at least one fic out there with the soulmate's-name variant wherein some thought was applied; there's a registry where you can file your Name and your basic details (birth date/time, etc.) and they attempt to find your soulmate, or notify you when the soulmate registers! A thoroughly rational approach that takes into account human curiosity and present-day levels of technology.
Mostly, though, it's one of those tropes that you Just Accept The Premise And Go From There; I mean, there's no scientific explanation on Earth for it, given that, y'know. Souls. If you believe in a soulmate, you have to believe in souls, and it follows that souls can Just Do Stuff that mere matter and energy can't. In fact, the one soulmate-fic I can recall giving a clear explanation was essentially that: the handprint that appears on you is created when your soulmate's soul reached out and touched you. Why that would leave a mark, or why that mark would later change colour in response to a physical touch when proximity wasn't required the first time? Still not explained. *shrug* I can usually muster the suspension of disbelief required, and when I can't I spend my time like you do, poking at the holes. :D
(Honestly, though, it's the A/B/O trope I think fails most at worldbuilding; unlike soulmates, it pretends to be biological -- blah blah pheromones this blah blah hormonal patterns that -- and yet it virtually never addresses the most basic worldbuilding details. Pheromones are so amazing that no one in the course of history has thought to apply basic chemistry to the problems they cause; nobody finds the legal implications of heat to be at all problematic or to affect the precedents of other cases; no one ever even seems to explain what alphas/omegas do in terms of the rest of human biology - I mean, why have men who can reproduce only with each other? You've designed humans with four sexes, and in some cases a "species" where half of it can't breed with the other half; how does that even work in terms of population limits? Or for that matter in terms of the scientific definition of a species? Nope. My suspension of disbelief is strong enough to handle souls touching each other, but not a sapient mammal species that doesn't want to alter their own biology for fun or profit.)
no subject
Aside from names or first words (and as others have said: HOW MANY people's first words to their soulmate would be something like "Hi" or "Welcome to McDonalds, can I take your order?"! Not at all helpful, and prone to lots and lots of false hopes being raised only to be broken.) I think the thing I've seen most is hand- or fingerprints, which does make more sense -- in the context of "literacy is not universal" -- than words do. And I've seen at least one fic which used symbols (somebody's characteristic weapon, e.g.) rather than words/names, too.
Oh, and there *is* at least one fic out there with the soulmate's-name variant wherein some thought was applied; there's a registry where you can file your Name and your basic details (birth date/time, etc.) and they attempt to find your soulmate, or notify you when the soulmate registers! A thoroughly rational approach that takes into account human curiosity and present-day levels of technology.
Mostly, though, it's one of those tropes that you Just Accept The Premise And Go From There; I mean, there's no scientific explanation on Earth for it, given that, y'know. Souls. If you believe in a soulmate, you have to believe in souls, and it follows that souls can Just Do Stuff that mere matter and energy can't. In fact, the one soulmate-fic I can recall giving a clear explanation was essentially that: the handprint that appears on you is created when your soulmate's soul reached out and touched you. Why that would leave a mark, or why that mark would later change colour in response to a physical touch when proximity wasn't required the first time? Still not explained. *shrug* I can usually muster the suspension of disbelief required, and when I can't I spend my time like you do, poking at the holes. :D
(Honestly, though, it's the A/B/O trope I think fails most at worldbuilding; unlike soulmates, it pretends to be biological -- blah blah pheromones this blah blah hormonal patterns that -- and yet it virtually never addresses the most basic worldbuilding details. Pheromones are so amazing that no one in the course of history has thought to apply basic chemistry to the problems they cause; nobody finds the legal implications of heat to be at all problematic or to affect the precedents of other cases; no one ever even seems to explain what alphas/omegas do in terms of the rest of human biology - I mean, why have men who can reproduce only with each other? You've designed humans with four sexes, and in some cases a "species" where half of it can't breed with the other half; how does that even work in terms of population limits? Or for that matter in terms of the scientific definition of a species? Nope. My suspension of disbelief is strong enough to handle souls touching each other, but not a sapient mammal species that doesn't want to alter their own biology for fun or profit.)