This also applies to Select-To-Speak if its voice is set to an Acapela voice in its settings. 

Two more errors from inspecting the Acapela extension:

_generated_background_page.html:1 Uncaught (in promise) error
Promise.then (async)
speakListener @ acapela_tts_engine.js:72
EventImpl.dispatchToListener @ extensions::event_bindings:403
publicClassPrototype.(anonymous function) @ extensions::utils:138
EventImpl.dispatch_ @ extensions::event_bindings:387
dispatchArgs @ extensions::event_bindings:260
(anonymous) @ extensions::ttsEngine:19
dispatchEvent @ extensions::event_bindings:267


wasm_tts.js:1 E_BAB: -34 E_BABILE_LICENSE
Module.printErr @ wasm_tts.js:1
put_char @ wasm_tts.js:1
write @ wasm_tts.js:1
write @ wasm_tts.js:1
doWritev @ wasm_tts.js:1
___syscall146 @ wasm_tts.js:1
<WASM UNNAMED>
<WASM UNNAMED>
<WASM UNNAMED>
<WASM UNNAMED>
<WASM UNNAMED>
<WASM UNNAMED>
<WASM UNNAMED>
Module._tts_init @ wasm_tts.js:1
ccall @ wasm_tts.js:1
(anonymous) @ wasm_tts.js:1
changeSpeechFont @ tts_shell.js:358
(anonymous) @ acapela_tts_engine.js:57
Promise.then (async)
speakListener @ acapela_tts_engine.js:28
EventImpl.dispatchToListener @ extensions::event_bindings:403
publicClassPrototype.(anonymous function) @ extensions::utils:138
EventImpl.dispatch_ @ extensions::event_bindings:387
dispatchArgs @ extensions::event_bindings:260
(anonymous) @ extensions::ttsEngine:19
dispatchEvent @ extensions::event_bindings:267

Acapela voices not working is definitely a problem but it may be somewhat out of our control. We need to focus this bug on errors that go beyond that - i.e. a broken Acapela voice causing problems even when you try to use speech from a system voice.

More questions:

You said S2S doesn't speak when you choose Acapela voices, but it does work again if you choose a system voice, right?

If Acapela is installed and not working, can you get ChromeVox to speak by selecting a system voice in the ChromeVox settings? What about if you reboot with ChromeVox off, then turn ChromeVox on so that Acapela hasn't even tried to speak once?

What happens if you disable the Acapela extension rather than uninstall it? Does ChromeVox start speaking again?

What happens if you try to speak using Web Speech Synthesis demo pages (search for it on Google, there are several pages where you can try out web speech)? When you use one of those pages can they speak with either Google or Acapela?

In the Acapela options page can you get speech?

None of the logs you're showing here are obvious errors. Any warnings about M70 should be irrelevant if this is M69 - if we see any difference in behavior in M70 then that could be relevant.

Does this happen with other Acapela voices? I can give you a gift card or something so you can purchase lots of voices if needed.

Can you reproduce this again if you uninstall Acapela, then install and re-download a voice?

Google Chrome	69.0.3497.21 (Official Build) dev (64-bit)
Firmware Version	Google_Lulu.6301.136.57

I'll answer your questions in individual comments so you can refer to comment number when addressing them. 

"You said S2S doesn't speak when you choose Acapela voices, but it does work again if you choose a system voice, right?" 

# Turn on STS from Settings or the status bar + test anywhere to ensure it is working as expected. 
# Install Acapela TTS Engine Extension: https://chrome.google.com/webstore/detail/acapela-tts-engine/hfpbgbaepoblbkbmpojjnpkeikgoadil
# Download any purchased voice (I purchased and downloaded French Anais/Belgain French AnaisBE, and English Willoldman)
# Go to Settings > Manage a11y > STS settings (chrome-extension://klbcgckkldhdhonijdbnhhaiedfkllef/options.html) 
# Under select a voice, use Acapela English WillOldman
# Invoke the STS feature anywhere
Expected: highlight appears, word highlighting happens, voice speaks
Actual: focus highlight disappears after drawing, no word highlighting, no voice
# Under select a voice, use Acapela Anais - French and repeat steps.
Actual: no focus highlight, word highlighting, nor voice
# Under select a voice, use Acapela AnaisBE - Belgain French and repeat steps.
Actual: no focus highlight, word highlighting, nor voice
# Under select a voice, use Chrome OS US English and repeat steps.
Actual: After switching back to English, try to invoke the feature nothing happens on the first time, no voice/highlight. However, it works as expected all times after that. 

Google Chrome	69.0.3497.21 (Official Build) dev (64-bit)
Firmware Version	Google_Lulu.6301.136.57

"If Acapela is installed and not working, can you get ChromeVox to speak by selecting a system voice in the ChromeVox settings? What about if you reboot with ChromeVox off, then turn ChromeVox on so that Acapela hasn't even tried to speak once?" 

Steps:
# Enable ChromeVox with ctrl + alt + z
# Go to ChromeVox settings via Settings menu or going here: chrome-extension://mndnfokpggljbaajbnioimlmbfngpief/chromevox/background/options.html
# Change Select Current Voice to be Acapela Willoldman - English
Expected: normal behavior
Actual: No speech, text is still shown on the speech viewer at the top of the screen along with this exact error message:


TTS Engine ERRORS: left brace quote value quote :-34, quote name quote : quote E_BABILE_LICENSE quote right brace


# With Acapela voice still used, turn ChromeVox off, wait a sec, then turn back on again. Chrome crashes, screen turns black. (Nothing in chrome://crashes) System recovers itself, ChromeVox briefly speaks in Chrome OS US English, then reverts back to Acapela Willoldman - English and exhibits the same problems as above. 
# After this, go back into ChromeVox settings, set voice back to Chrome OS US English, starts speaking again as expected. 

# Set ChromeVox settings voice back to Acapela Willoldman. Voice stops speaking. 
# Turn off ChromeVox with CTRL + Alt + z
# Reboot Chromebook
# Go through logon screen, sign back in 
# Turn on ChromeVox again. It speaks in Chrome OS US English for a few seconds, then goes back to not speaking like described above
# Go back to ChromeVox settings, set voice to Chrome OS US English, works as expected again

Google Chrome	69.0.3497.21 (Official Build) dev (64-bit)
Firmware Version	Google_Lulu.6301.136.57

"What happens if you disable the Acapela extension rather than uninstall it? Does ChromeVox start speaking again?"

Unable to repro that one-time error state above where ChromeVox stops speaking even after being switched back to Chrome OS US English. That said, I tried these steps:

# Enable ChromeVox
# In ChromeVox settings, set voice to Willoldman English
# In the extensions area next to the Omnibox, select "Remove from Chrome for Acapela Extension
# ChromeVox resumes speaking, has automatically switched to top item in the list for languages, Chrome OS Bahasa Indonesian
# Turn ChromeVox off and on again, go to its settings, voice is now set to Chrome OS US English

Google Chrome	69.0.3497.21 (Official Build) dev (64-bit)
Firmware Version	Google_Lulu.6301.136.57

"In the Acapela options page can you get speech?"
Yes. If you press the "play" button next to a voice it speaks. 


"Does this happen with other Acapela voices? I can give you a gift card or something so you can purchase lots of voices if needed."
Since I tried it with three voices, I feel like I'm covered. 

"Can you reproduce this again if you uninstall Acapela, then install and re-download a voice?"

I can reproduce everything above since I did that before today's tests. However, I've been unable to get the original error where ChromeVox won't speak even when switched back to Chrome OS US English. It speaks properly after the change every time now.

Deleted comment 8, I wrote it in an unclear way. Results below. 

Google Chrome	69.0.3497.21 (Official Build) dev (64-bit)
Firmware Version	Google_Lulu.6301.136.57 

"What happens if you try to speak using Web Speech Synthesis demo pages (search for it on Google, there are several pages where you can try out web speech)? When you use one of those pages can they speak with either Google or Acapela?"

I tried several web speech demos with Chrome OS US English without any Acapela voices installed at all: 
https://developer.microsoft.com/en-us/microsoft-edge/testdrive/demos/speechsynthesis/
https://codepen.io/matt-west/pen/wGzuJ
https://eeejay.github.io/webspeechdemos/

All work as expected. 

Now trying those websites with Acapela WillOldMan installed but NOT selected. I kept Chrome OS US English selected. On all three sites, nothing was spoken as soon as Acapela was installed! 

Setting the languages to Acapela WillOldMan also resulted in not speaking. 

I then uninstalled Acapela extension, refreshed the pages, and tried the three websites above. They no longer spoke with Chrome OS US English selected. 

Google Chrome	70.0.3511.0 (Official Build) canary (64-bit)
Firmware Version	Google_Eve.9584.160.0

Test 1, test speech with Chrome OS US English selected, Acapela not installed:
https://developer.microsoft.com/en-us/microsoft-edge/testdrive/demos/speechsynthesis/
https://codepen.io/matt-west/pen/wGzuJ
https://eeejay.github.io/webspeechdemos/

All work as expected.

Test 2: install the Acapela extension but don't download a voice. 

All work as expected. 

On this machine, I'm unable to download Acapela voices right now. Please let me know if there is more data I can provide in the future.

Remote voices list unavailable {"ERROR":"404","url":"https://andrvcechrm.acapela-group.com/index/getnonce"}
Downloading https://andrvcechrm.acapela-group.com/index/getnonce failed, HTTP failure status code: 404.
ACAPELA TTS create OK

Google Chrome	70.0.3532.8 (Official Build) dev (64-bit)
Firmware Version	Google_Caroline.7820.384.0

No longer reproduces with Acapela voices Willoldman and Anise. I was able to change the settings in the global TTS and in the individual screen reader settings and it spoke as expected.