I am trying to find the API for Windows Voice Access. Microsoft .NET docs are confusing as its not clear what recognition backend Windows Voice Access or (SAPI) 5.3 is being used.

If I run code system.speech.recognition it seem to use (SAPI) 5.3 not Windows Voice Access

SpeechRecognitionEngine.SetInputToWaveFile Method for (SAPI) 5.3 loads a file to be recognition and execute a recognized command form a grammar.