Stuff like this is exactly what I was hoping someone would know of for me! Thank you!
Sadly, when I followed the paper trail for this looking for an english translation; Turns out its all silly nonsense translated with google and not actually scientific theories or ideas lol
But I did find his sketch which is gorgeous.
The flaccid tongue was one of the best inventions Resurrection had, but is it just another by-product of the cloning? I would like to think the tongue on a "pure-bred" Alien is the same. Although if the tongue is a completely solid piston, it would explain partially why the head is so long?
I like the flaccid tongue idea as well, with it being quite soft and bendy when not used to attack. It seems very fitting for the overall design to have- Like Elmazalman and SM state about it being like a penis. Perhaps even prehensile which is shown in some movies where it does bend for the sides slightly to 'wiggle' this isn't unlike how whales reproductive organs work (while still being able to tuck away of course).
As for Resurrection (1997) I went back to have a really close look at how their mouth parts work in it and remembering that Ripley 8 is 'super strong' thanks to the cloning process- she is able to completely bend the tongue when flaccid in a very compact way. I grabbed some screen shots, banged the brightness up and tried to go over them to illustrate this point and also looked hard at the torn end which??? Looks a lot like the chameleon inspired design with the elastic skin and the tendons?
Perhaps when the inner mouth is lined up with it's inner rod (the firing piston) it is extremely strong and can fire the toothed end off like a bolt gun. But when pushed from the sides or using the internal muscles to shift it around, its very soft and malleable.
Would the inner mouth be attached to the upper (skull) or lower jaw as well?
Also I made a new theory about their inner mouths and it is by far the best theory of them all.