String aus Dialog Fragment an Activity zurück geben

btnAddLang.setOnClickListener(new OnClickListener() {            
            @Override
            public void onClick(View v) {
                FragmentManager fm = getFragmentManager();
                AddLanguageDialogFragment dialog = new AddLanguageDialogFragment();
                dialog.show(fm, "add_language_dialog");
                
            }
        });

public Dialog onCreateDialog(Bundle savedInstanceState) {        
        LayoutInflater inflater = LayoutInflater.from(getActivity());
        View view = inflater.inflate(R.layout.fragment_add_language, null);
        edTxtLanguage = (EditText) view.findViewById(R.id.edTxtLanguage);
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setView(view);
        builder.setTitle(getString(R.string.AddLanguageDialogTitle));
        builder.setPositiveButton(getString(R.string.ok), new DialogInterface.OnClickListener() {            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                //Hier soll dan der Text aus der EditText an die Activity zurück
                
            }
        });
        builder.setNegativeButton(getString(R.string.Cancel), new DialogInterface.OnClickListener() {            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();                
            }
        });        
        return builder.create();    
    }