And yet noise-cancelling phones not supposed to block speech!
When I went looking for noise suppressing headphones --- to use just purely for noise suppression, not to amplify any music or other audio source -- I found that all of them meant for aircraft use specify they allow the human voice range to be heard despite the noise suppression. Even the professional pilot units that I happened on, though I didn't look too long.
This is supposed to be a safety feature so you don't miss the peanut cart or evacuation announcement.
And I suppose it is.
I found the answer was to double up thick compressable foam earplugs and over those a big hefty set of shooter/construction noise blocking earmuffs.
Of course if they'd announced an evacuation I wouldn't have heard a word.