code: public String posTagging(String text){
  		String ret = text;
  		if (vnPosTagger != null){
  			ret = vnPosTagger.tagging(text);			
  		}
  		
  		return ret;
  	}
docs: Do pos tagging.
  
  @param text to be tagged with POS of speech (need to have words segmented)
  @return the string