MacOS Say Command Hangs Writing to a File

Question

For many years I've been using the say command to read back essays I've written. My workflow is

1. Use say to write out an aiff or WAVE file
2. Use an audio player like iTunes to playback the file, pausing and rewinding as needed

However, recently the say command started to hang when I used it with an input and output file.

$ ls -lh /tmp/md_to_sayfbfhyf.txt
-rw-r--r--@ 1 alanstorm  wheel   5.8K Jan  5 08:59 /tmp/md_to_sayfbfhyf.txt

$ say -f /tmp/md_to_sayfbfhyf.txt -o output.aiff

This command will hang after writing a little over a MB to the aiff file.

$ ls -lh output.aiff
-rw-r--r--  1 alanstorm  staff   1.1M Jan  5 09:13 output.aiff

After that say will always hang unless I kill speechsynthesisd.

Also, this appears to be a problem with writing the output file -- running just

$ say -f /tmp/md_to_sayfbfhyf.txt

works without issue.

I'm on MacOS: 10.13.4 (High Sierra)

The command works with very small text files that contain a sentence or two -- but files with more than a few paragraphs of text hang. I have not zeroed in on a specific file size or word count.