Here's more information.
Dictation attempted to QTextEdit and QTextLine derived controls.
Qt-5.6.2 with SDK-12 and Xcode-8
and 5.4.2 with previous set - on Mac OS 10.12 Sierra.
With any other software (Firefox, Pages, etc) after "Start Dictation"
the Edit menu (or twice command key at keyboard) appears
a nice microphone window and one is able to dictate to the window.
With my Qt applications there's a sound heard after
after "Start Dictation", but no microphone window
and no dictation seen.
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