It is now very easy to use the speech to text feature provided by Android. Please follow the following steps to know hoe to use this feature:

1. Create an activity and with a textview to show the text and a button to initiate the speech to text service.

2. on the click of button, call the following intent as:

Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, Locale.getDefault());
intent.putExtra(RecognizerIntent.EXTRA_PROMPT,"Speak now");
        try {
            startActivityForResult(intent, REQ_CODE_SPEECH_INPUT);
        } catch (ActivityNotFoundException a) {
            Toast.makeText(getApplicationContext(), "This feature is not available for your device", Toast.LENGTH_SHORT).show();
        }

After this request, the result can be found inside onActivityResult method as:

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        switch (requestCode) {
        case REQ_CODE_SPEECH_INPUT: {
            if (resultCode == RESULT_OK && null != data) {

                ArrayList<String> result = data
                        .getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
                txtSpeechInput.setText(result.get(0));
            }
            break;
        }

        }
    }

Inside above method, we're setting the recognized text in textview.