Dictation not working on iMac 27 (2017)

Hi all,

I cannot setup enhanced dictation on the new iMac 27.

The menu Start Dictation under Edit is grayed out and Fn Fn does not work either (I hear a beep of invalid command).

However, when I activate advanced commands in Accessibility section, Fn Fn starts working (but not the Start Dictation menu), and a small windows appears at the lower-right corner of the screen. The computer can hear me, but recognition is quite inaccurate. Sometimes the command I dictate just shows up above the dictation window, but is not executed. When I try to dictate large chunks of text, it’s very inaccurate, sometimes it does not react at all, so I need to repeat the same phrase several times.

What I need to activate is another window: “When your Mac is listening, it displays a microphone to the left or right of the page, aligned with the insertion point.” as stated in this article: https://support.apple.com/en-us/HT202584 But it never shows up.

I can easily dictate in a Google online service on the same iMac, and pretty fast, so the microphone is operational. I also switch between the internal microphone and a specialized voice recognition USB headset, and both are fine.

I’ve been trying to solve the issue for a few days, following any possible advice I could find online.

I tested the function in a new administrator account, reinstalled High Sierra, installed it on a new partition and even upgraded to Mojave to check if the issue is connected to the OS, but still nothing.

Here how it goes:

1. After I first login (newly installed OS), the Start Dictation menu line under Edit is active.
2. I click it (or Fn Fn), and the dialog pops up asking if I want to configure dictation.
3. I click Yes and am prompted to the Dictation settings under Keyboard in System Preferences.
4. I switch the Dictation on and a window pops up saying “Dictation languages aren’t available to download at this time. Try again later.” I think at this point (hard to tell exactly, maybe even earlier) the Start Dictation menu line becomes grayed out / inactive.
5. Eventually, after I open “Add new language” drop down menu, I manage to download the language package. But the dictation does not work.

What could be the reason? Is it an OS error, a driver, the dictation module, the network? It’s frustrating since dictation was the main reason for buying the Mac. Could I solve it if I install an earlier OS version like Sierra? Or maybe I could copy some folders from a machine where this function works well?

I would appreciate your help.