Well, is it low or high?  “Hush” is calming, but it’s also a word of caution.  I like that it’s missing from Chapter 8 through 18.  I’m going to label it “low”, but that does not satisfy: what I mean is that it’s a peaceful word for use in the Shire and among elves except when warning others not to notice a certain giant bear.

• 01.004 and the family hushed it up;
• 01.089 Hush!’ said Gandalf.
• 03.029 “Hush, hush! Good People!
• 03.029 “Hush, hush! Good People!
• 07.133 ‘Hush! Take no notice!’
• 19.014 Hush! Hush! Oak, Ash, Thorn!
• 19.014 Hush! Hush! Oak, Ash, Thorn!
• 19.014 Hushed be all water, till dawn is at hand!