Thank you very much for your beautiful paper on the Kebara hyoid. I fully agree with your conclusion that it might have been compatible with humanlike speech in neandertals, but speech was probably not the reason why it evolved that way.
Comparative data suggest that most differences between Homo & the apes in mouth & throat anatomy might best be explained by an adaptation in archaic Homo for swallowing soft & slippery foods without much biting or chewing. Compared to chimps, humans have a flatter face, a much smaller mouth opening, a shorter oral cavity with the hyoid bone descended in the neck (Nishimura), a parabolic & closed tooth-row with incisiform canines, a smooth & vaulted palate, a smooth & globular tongue (allowing better suction), inactivation of the myosin heavy chain MYH16 gene (dentitional musculature) etc.
We suggested all these were adaptations for swallowing soft, wet & slippery foods when Pleistocene archaic Homo dispersed along coasts & rivers as far as Indonesia (eg, Mojokerto, Flores), southern Africa (eg, Namibia, the Cape) & England (eg, Pakefield, Boxgrove) and consumed a lot of aquatic & waterside foods.
For more information, google "Greg laden blog Verhaegen" & "econiche Homo" or send me an email.
Human Evolution publishes in 2 special editions the proceedings of the symposium with David Attenborough & Donald Johanson on human waterside evolution "Human Evolution: Past, Present & Future" in London 8-10 May 2013.
Special Edition Part 1 (end 2013): Peter Rhys-Evans "Introduction", Stephen Oppenheimer "Human's Association with Water Bodies: the 'Exaggerated Diving Reflex' and its Relationship with the Evolutionary Allometry of Human Pelvic and Brain Sizes", JH Langdon "Human Ecological Breadth: Why Neither Savanna nor Aquatic Hypotheses can Hold Water", Stephen Munro "Endurance Running versus Underwater Foraging: an Anatomical and Palaeoecological Perspective", Algis Kuliukas "Wading Hypotheses of the Origin of Human Bipedalism", Marc Verhaegen "The Aquatic Ape Evolves: Common Misconceptions and Unproven Assumptions about the So-Called Aquatic Ape Hypothesis", CL Broadhurst & Michael Crawford "The Epigenetic Emergence of Culture at the Coastline: Interaction of Genes, Nutrition, Environment and Demography". Special Edition Part 2 (begin 2014) has 12 contributions.