code: private void parseMainVowel() {
  		if (!validViSyll)
  			return;
  		if (iCurPos > strSyllable.length() - 1) {
  			validViSyll = false;
  			return;
  		}
  
  		String strVowel = "";
  		for (int i = iCurPos; i < strSyllable.length(); ++i) {
  			int idx = vnVowels.indexOf(strSyllable.charAt(i));
  			if (idx == -1)
  				break;
  
  			strVowel += vnVowels.charAt((idx / 6) * 6);
  			if (tone.getValue() == TONE.NO_TONE.getValue())
  				tone = TONE.getTone(idx % 6);
  		}
  
  		Iterator iter = alMainVowels.iterator();
  		while (iter.hasNext()) {
  			String tempVowel = (String) iter.next();
  			if (strVowel.startsWith(tempVowel)) {
  				strMainVowel = tempVowel;
  				iCurPos += tempVowel.length();
  				return;
  			}
  		}
  		validViSyll = false;
  		return;
  	}
docs: Parses the main vowel.