Dictation using Thunderbolt Display as Audio Input source does not work on new MacBook Pro & Catalina

Solved it! I have 2019 MacBook Pro with an external Apple Monitor. In order to get dictation working in clamshell mode, I had to enable Voice Control.

1. Choose Apple menu  > System Preferences, then click Accessibility.
2. Click Voice Control in the sidebar. 
3. Enable Voice Control

Hope this helps!

Sorry this didn't fix it... Have you looked into the Permissions (a lot have changed there in Catalina). Go to your "System Settings" and choose "Security & Privacy" then on the "Privacy" tab find the "Microphone" list item (left pane). From the right pane, look to see if your app shows up and if so, make sure it is selected (checked).

Other than that, I'm not sure what else I can suggest.

~Mark

I have a brand new Macbook Pro (2019) and I use the same monitor (which worked fine before the Catalina update). I reset my Mac's SMC (On the Mac's built-in keyboard, press the left side Shift-Control-Option keys and the power button simultaneously). I was also going to reset the NVRAM or PRAM (Press and hold the Command-Option-P-R keys immediately after you hear the startup sound - Hold these keys until the Mac restarts and you hear the startup sound for a second time), however the first option fixed it for me.

Try resetting your Mac's SMC and see if that works.

~Mark

I have this same issue with my 2019 16" MPB and 2019 LG UltraFine Display (27").

Dictation works fine (both through the internal MBP mic and through the UltraFine Display mic) when the MPB is open.

However, when the MPB is in clamshell mode (how I use it most of the time), Dictation does not work (through either mic) despite the UltraFine Display mic working just fine for FaceTime, etc. When I try to use Dictation, the little mic icon that pops up does not show any activity when I speak.

I believe there is likely a bug that causes Dictation to disable even external mic input when the MPB's lid is closed. I really hope there is a fix for this forthcoming.

I have the same issue with my MacBook Pro 13 inch base model mid 2019. I spent a couple of hours on the phone with Apple Support and they tried some workarounds, which I don't recall as they had no effect, but for now according to their information it is functioning correctly in accordance with the T2 security chip security protocols. Despite the contradiction that all other audio input but dictation works fine with my external microphone, as I demonstrated to them on screen share. On the current OS version, the only way that the dictation input can work from an external microphone is if the clamshell is open.

Another oddity I noticed is that when the dictation input cancels mid sentence after a certain amount of time and then immediately pastes the exact same thing--duplicating what it already dictated in the text field. So after each dictation cuts out you have to delete the duplicated text.

Having just switched from windows, I'm very disappointed at the unreliability of these basic functions. I didn't have these issues with Windows although I don't know if you can close the clamshell on a Windows laptop and still use an external monitor. In any event, there is seemingly no resolution now but the support person I spoke with indicated they would pass on this support forum number to the engineers. I guess we can hope it is fixed in the next update.

I reported this to Apple support in December 2019 and someone in their senior support team in Ireland very helpfully replicated the issue using their own equipment. This is the response I had from the engineering team as it seems to be a recognised issue:

"They have advised that they have received reports of this symptom and are investigating. Further updates, if any, may come by way of a software update, knowledge base article or software release." 30 December 2019.

Also for information rather than using standard Dictation mode (System preferences / Keyboard/ Dictation), if you use 'Voice Control' instead (System preferences / accessibility/ Voice Control) this does work if you have the Mac in clamshell mode while using an external monitor (with microphone) and doesn't 'time out' or stop with keyboard or mouse input like dictate.

However, set the language preference to English (United States) not English (UK) - otherwise the latency in the system is so great it becomes unusable. This is to do with the way the system interacts with Siri and the servers in the States apparently - if you're based in the UK dictation/voice control will grind to a halt...

Voice control was hugely buggy when I tried it. Just didn’t pick up my voice at times. And really just wouldn’t work reliably at all on latest Catalina. Also it’s annoying to have a constant microphone icon floating on screen. Keyboard shortcut is way more efficient. Or a hot word like “hey Siri enter text”. The keyboard shortcut is way easier and they should just get it to work.

No joy with 10.15.4 either. Crazy.

It is beyond me why Apple won't fix this issue. They absolutely know about it. I also contacted support a couple of months ago. I uploaded logs, and the issue was supposedly escalated to a higher level.

If I have a functional external mic that will work with every other service, let me use it with dictation! I would much rather keep using my MacBook Pro in clamshell mode than permanently opened up.

I am having the same issue on my 2018 15 inch MacBook Pro with a 27 inch Tunderbolt display running macOS Catalina 10.15.2 (19C57) hopefully they can patch this soon.

Thanks that was very helpful

Just commiserating, same issue with me. No luck even after the update. Voice Control also a little buggy. Apple please fix this!!