QSZ? means “Shall I send each word or group more than once?”
I hate to admit this, but I am far from perfect in copying morse code even at, say 35wpm. That is especially true with longer words, in which case I tend to miss the latter half of the word. So I thought it might help to repeat each word two or three times like this:
So so so I I I thought thought thought it it it might might might help help help…
% gawk '{print $0,$0,$0}' message.txt > message-rep3.txt
% ebook2cw -w 35 -W 3 -f 600 -s 8000 -b 16 -q 1 -o message-rep3-35wpm message-rep3.txt
Let’s see if I can get any words at least after the final repeat.