SpeechToTextKeywordsThreshold Property

NON-MULTIPART ONLY: Confidence value that is the lower bound for spotting a keyword. A word is considered to match a keyword if its confidence is greater than or equal to the threshold. Specify a probability between 0 and 1 inclusive. No keyword spotting is performed if you omit the parameter. If you specify a threshold, you must also specify one or more keywords.

public Nullable<float> KeywordsThreshold { get; set; }