@gaditb okay extremely cool pull, but ngl my second reaction (the preceding having been both my first and third reactions) was "damnit this also has no discussion of how or why they continue to fly the possibly formerly better route instead of a now more direct one"

@gaditb @alyssa dont wanna get lost over a giant lake, and they know this one works, I guess?

@Satsuma @gaditb how do they know it works tho

@alyssa @gaditb well, it has every year for the last millennia apparently so it seems p safe to me

@Satsuma @gaditb well i think it's probably a safe assumption that the butterflies don't know that. my question is how do they know what route to take (and how does that knowledge get preserved through the presumed millennia)?

@alyssa @gaditb well, not just over the lake, they’d have to remap their whole route if they skipped the going east bit, and would potentially end up in areas without sufficient food/water or that have already been depleted by other groups of monarchs

@alyssa corollary here is that oftentimes it is the fact that there are distinct allophones which ALLOWS the bit of surrounding context to be safely discarded, because the allophones are now conveying whatever information the (usually more verbose) preceding thing was doing

@Lady ah that corollary's an interesting point. see, this is why books about historical linguistics should talk about this issue :P

do you know if cases are known where a conditioning environment for allophonic variation was lost and the former allophonic variation was also simply lost rather than splitting phonologically?

@alyssa i think this is a difficult question to answer because frequently we only know about these things because someone considered it distinctive enough to remark upon, which is usually not the case for ordinary allophones

much of our knowledge about historical phonology comes from things like poetry, but oftentimes poetic rhyming conflates various allophones (and if it doesn’t, that’s an argument in favour of the sounds being distinctive)

so “people used to say this a few different ways, but that variety vanished without consequence once the conditioning environment shifted” is something there is likely to be zero historical record of (except in the past maybe hundred years where people have started getting really rigorous about recording dialect and phonological systems exactly)

@alyssa (so, no i don’t know of any cases, but moreover i don’t know HOW we would know)

@Lady the indo-aryan languages seem like the main spot where it might plausibly be observable (due to combination of being one of the most studied families in historical linguistics and of having a very ancient literature on phonetics)

but yeah more modern synchronic observation seems more likely to turn up cases if it exists, and certainly we know of some ongoing cases of loss of conditioning environment resulting in phonemic split of former allophones from synchronic observation.