1. a whispering or rustling sound
With etymologies out of the way, let's have a look at these guys. These creatures are aberrations (somewhat unsurprisingly) with 8 RHD. Ability scores are nothing out of the ordinary, with high strength, good constitution and charisma, and average-to-low stats everywhere else.
Two natural claw attacks are kind of meh, +9 natural armor has its uses, 40 ft. land and 20 ft. climb is decent speed-wise. 60 ft. blindsight isn't bad to have (but being sightless beyond that radius is less great).
The susurrus has a number of undead-focused abilities: always-on Detect Undead, a weird rebuke-based Hold Undead, and free Ghost Touch. Furthermore, it gets Improved Grab and Barbed Defense (which deals piercing damage to melee attackers and grapplers).
Ultimately, I'm just unimpressed by the susurrus. When not facing undead foes, it has a chassis comparable to the ogre's but with twice the RHD and little extra to show for it. Against undead, it has a notable niche with Dronesong, but that's too situational to greatly impact the rating. I'm simply not convinced this stacks up to ECL 8 martials, so -0 LA it is. If you want to balance this for player use, remove three HD and it should be fine.