Solutions for Act I Scene 3 - Echo

We are presented with a list of strange descriptions and corresponding incomplete strings of words. It should be straightforward enough to fill out the letters replaced by question marks, giving:

broken chord feels unwell arpeggio ails
rebellion defiance
examine NSW beer painting study Tooheys arT
storm in direction of seaside air blizzard to ozone
guy to be indebted to nation fellow owe empire
Sydney suburb flat Dee Why even
chiropractor cooler physio esky
prophesy one garden foresee a yard

The parts left out don't seem to be words themselves or anagrams, but the title Echo suggests we want to say the phrases out loud and listen back on them. Doing so should make evident the fact that the bolded sections are sounding out letters themselves (sometimes unconventionally, e.g. "Tooheys" sounds like "two E's"). In fact sounding out each line in turn, we get the following string of letters, noting each line supplies a new word: GOAL-FIN-DEER-ZOO-LOOM-EYE-COS-CAR.

These words don't seem to have anything in common, so maybe we should look to the theme again to work out the next step. The previous step involved reading out some sounds to give letters that spelled new words. Sounding out the new string of words doesn't seem to give conventional letters, but the trick here is to notice the string does sound out letters from the NATO phonetic alphabet. This is hinted at again by the title, since Echo is the NATO word for the letter E.

In this light, sounding out the word string gives GOLF-INDIA-ZULU-MIKE-OSCAR. These correspond to the letters GIZMO, giving an answer that perhaps describes the device this particular puzzle was found on.

The answer is: gizmo