android官方demo中提供文件识别，请问我想进行英语pcm文件识别，应该怎么修改？

private ArrayList getTests() {
ArrayList cases = new ArrayList();

Map defaultParams = new HashMap();
defaultParams.put(SpeechConstant.ACCEPT_AUDIO_VOLUME, false);
defaultParams.put(SpeechConstant.VAD, SpeechConstant.VAD_DNN);
// defaultParams.put( "lan", "en");
// =========================
Map params = new HashMap(defaultParams);
cases.add(new SpeechTestCase("firstTest", "16k_test_1.pcm", params));
// =========================
Map params2 = new HashMap(defaultParams);
cases.add(new SpeechTestCase("secondTest", "16k_test_2.pcm", params2));

Map params3 = new HashMap(defaultParams);
cases.add(new SpeechTestCase("thirdTest", "16k_test_3.pcm", params3));

cases.add(new SpeechTestCase("fourTest", "outfile.pcm", params));
return cases;
}