Calculate The Delay of The Recording File

I'm building an application to calculate delay based on keywords found. The method I used is not accurate or even wrong (error). The methods used are as follows:

@Override
public void onResults(Bundle results) {
    progressBar.setVisibility(View.GONE);
    ArrayList<String> matches = results.getStringArrayList(SpeechRecognizer.RESULTS_RECOGNITION);

    if (matches != null && !matches.isEmpty()) {
        String transcript = matches.get(0);
        textSTT.setText(transcript);

        if (transcript.contains(keyword)) {
            long endTime = System.nanoTime(); // Using nano
            delay = endTime - startTime;

            double delayInSeconds = delay / 1_000_000_000.0;
            double roundedDelay = roundToTwoDecimalPlaces(delayInSeconds); // Rounding delay

            delayResult.setText(String.format("Delay: %.2f seconds\nTranscription result: %s", roundedDelay, transcript));
        } else {
            delayResult.setText("Keyword not found.");
        }
    } else {
        delayResult.setText("No result from speech recognition.");
    }
}

Condition:

• When I first press the button to start recording, after that I immediately mention the keyword (approximately the 1st second). But the results show the delay obtained is 2 or even more.

Tools:

• Speech Recognizer (Android default)

I have set 10 seconds for the countdown. When I pressed the button to start recording, I immediately mentioned the keyword (approximately the 1st second). But the delay result shows the 2nd second or even more. Similarly, when I try to mention the keyword at the 5th second, but the delay result shows the 7th second or even more.

I want the delay calculation to be more accurate, for example: I mention the keyword at the 7th second, then the delay is 7 seconds.