diff --git a/app/src/main/java/com/maxwell/speechrecognition/SpeechRecognition.java b/app/src/main/java/com/maxwell/speechrecognition/SpeechRecognition.java
index ad45845..98856ed 100644
--- a/app/src/main/java/com/maxwell/speechrecognition/SpeechRecognition.java
+++ b/app/src/main/java/com/maxwell/speechrecognition/SpeechRecognition.java
@@ -12,6 +12,8 @@
 import android.support.annotation.Nullable;
 import android.util.Log;
 
+import java.util.Locale;
+
 /**
  * Created by Maxwell on 13-Jan-18.
  */
@@ -86,8 +88,12 @@ public void setSpeechRecognitionPermissionListener(@NonNull OnSpeechRecognitionP
         this.onSpeechRecognitionPermissionListener = onSpeechRecognitionPermissionListener;
     }
 
-    public void setPreferredLanguage(){
-        throw new UnsupportedOperationException();
+    public void setPreferredLanguage(String preferredLanguage) {
+        recognizerIntent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, preferredLanguage);
+    }
+
+    public void setDevicePreferredLanguage() {
+        recognizerIntent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, Locale.getDefault().toString().replace("_", "-"));
     }
 
     /**
diff --git a/app/src/main/java/com/maxwell/speechrecognition/SpeechRecognitionPermissions.java b/app/src/main/java/com/maxwell/speechrecognition/SpeechRecognitionPermissions.java
index 878d677..e58e1cb 100644
--- a/app/src/main/java/com/maxwell/speechrecognition/SpeechRecognitionPermissions.java
+++ b/app/src/main/java/com/maxwell/speechrecognition/SpeechRecognitionPermissions.java
@@ -57,11 +57,14 @@ public void onRequestPermissionsResult(int requestCode, String[] permissions, in
 
             // If request is granted, the result arrays are not empty.
             if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
-                onSpeechRecognitionPermissionListener.onPermissionGranted();
+                if (onSpeechRecognitionPermissionListener != null) {
+                    onSpeechRecognitionPermissionListener.onPermissionGranted();
+                }
                 return;
             }
         }
-
-        onSpeechRecognitionPermissionListener.onPermissionDenied();
+        if (onSpeechRecognitionPermissionListener != null) {
+            onSpeechRecognitionPermissionListener.onPermissionDenied();
+        }
     }
 }