As I recall briefly commenting on this proposition in the Discord. What is considered a "sound-effect" is ambiguous in of itself and places guesswork on a tagger or translator if what is written is of sufficient "substance" or not to warrant the use of the tag. I will list a few common scenarios below of posts that have been added to this tag, where I will walk through at least my thought process as a translator as to whether or not they should be tagged as such.
Scenario 1 - Audible Noises:
When the text is representing an audible noise.
post #2421237 - Posts like this fit the definition of what is considered a sound effect. The text is directly mimicking the noise of a camera shutter and I could logically see this post being in sound_effect_only_translation.
post #2199180 - Directly representing the noise of a fluid spraying out of a bottle. An SFX.
Scenario 2 - Action/Conduct Representations :
When the text is representing an action, be it passive or direct, that doesn't literally make noise.
post #2464110 - The text is representing the action of intently staring at something. Is the passive action of staring at something a "sound effect"? Well if we're assuming that any descriptive text that isn't spoken dialogue is a "sound effect" than I suppose it would, but is that how we operate?
post #2471407 - The text is representing the act of squeezing, in this case a hug. It's expressing the degree of the physical action of the embrace which is being denoted as tight due to the squeeze. Again if we're operating on that any non-spoken descriptive text like this is a "sound effect", than I suppose it would fit.
post #6582654 - This text is describing that the breasts of the female have, in the moments before this scene, jiggled or as the note describes, "boing"s. Usage like this isn't directly describing any noise of sorts but rather that of a movement of an element in the image. Again, non-dialogue descriptive text = sound effect, so I guess this gets the tag.
post #2415882 - This text is describing the act of the turret petting Erika's head. We're describing an action and its not dialogue, into the tag it goes.
Scenario 3 - "Spoken" Audible Noises:
When the text is directly and audibly uttered.
post #2446075 - Two people going Aaaaa into a fan. Is this a sound effect? Well...no? maybe? They're "speaking", so this is dialogue-ish, just not of much "substance". Would I put it in the tag? No this isn't a sound effect imo, I wouldn't and searchers who would utilize -sound_effect_only_translation to avoid this "low substance" translation would be irritated seeing such.
post #2323391 - A slightly disgusted girl vocally exclaiming "Haaah?". A sound effect? Well no? She's speaking. Is it significant enough to "fit" into translated? Why does that call need to be made?
post #2390777 - Same as above, audible noise used in situations where one wishes to be fed by another. Sound effect? No.
post #2420746 - Wan wan wan wan... Noises of dogs barking. An effect? Ehhh?
Scenario 4 - Mixtures Of Noise & Action:
When the text is mimicking an action and giving off a noise.
post #2431463 - Flandre eating some cake and the noise of "paku" is given off to represent the noted "bite". This one is not only describing the action of her placing food in her mouth, but also is mimicking a minor noise, akin to someone going "Aahmn" when going to eat something. Sound effect? Well, it is a sound and is describing an action at the same time. When does a sound stop being an effect? Now you might be going,
come you're being overly analytical, it's clearly a sound effect' which I could see defined as such, I merely wish to express to you that the uses of these are broad and can take place of spoken speech which creates a grey zone of when something is and isn't an effect. Like the following:
post #2147520 - Nya- Utilized for both the noise, and oft cat-like gestures. similarly post #2105431, no evidence of spoken noise, but there's a cat, so the artist used Nya- for cat-ly-ness. Is it an effect? Do we assume the cats audibly cried and consider it a noise, does that matter when we tag this? Uh I'm not sure. Again I'd like to emphasize this very hesitation to and understand the burden of having to make a judgement call on when something is and isn't an effect considered an effect.
post #2422498 - A flag flapping in the wind, giving off the noise of "pata pata" and representing its movement in presumably a breeze of sorts. Sound effect? I suppose so.
post #2325915 - Hawawa. The girl's potentially audible noise that is describing her flustered state. While possibly the actual noise of her attempting to speak or just vocally expressing her flustered-ness, it also could just inferred as non verbal and merely a descriptor of her embarrassed state. Which is it? I don't know. Do I need to know and just assume, well it's not dialogue so whatever, into the sound_effect_only_translation it goes? Again, I have to make this judgement call or just not care and pick one or the other.
I could go on adding more posts and categories but I think I've expressed that in some cases, there's black and white, yeah this post is just effects, and some that are well..., and as a tag to fundamentally require an individuals judgement to go well... is this an effect? is possibly just a mess waiting to need cleaning and frankly an annoyance I for one would dislike having to evaluate whether the substance in a post's notes are of enough "dialogue-y" merit to warrant utilizing this tag.
Even were we to alias to translated and have this an additional tag one could use as a minus search to weed these out, I'd point you toward the above entries where I went, "well..." and know that I and possibly other translators may not tag them as all the time and the users of such would probably still see these kinds of posts. Not to mention those who do not translate may use a translation as a basis for the decision as to which tag it would go in without actually knowing the original texts context that may or may not have weighed into such a choice. All in all, I again think this would just be a mess waiting to happen, and while I understand the desire for such separation, I don't believe there is a suitable tag for such as there's much gray area and at its core is based on an individuals judgement call as a tag. Thank for you reading.