To add onto the syrinx thing, that could add a new ability to the arsenal of reptilians, since it allows for mimickry, they could lure sound sensitive mobs and such, maybe. It's such a powerful adaptation for a sapient species capable of getting into the minds of their prey that it's somewhat difficult to not think of them with it(esp. since their livelihood is in hunting).
I don't know about reptilians but there is a myth I read about once,
about one of those really wide trees that can do that.
Might have been an oak or a weeping willow.
But it was one of those really fat trees with the wide outstretched branches.
Anyways.. It had some sort of knothole at it's base near the roots where it would mimic words from so people would investigate. Sometimes coming from a mile off cause the mimic voice could echo pretty well.
When people who found the tree, got close to the hole where they thought the voice was coming from,
the tree would suck them in like a vacuum and eat them alive with several circular rows of razor sharp pointy teeth descending into the hole.
Kinda like one of those grinder machines or a wood chipper might have.