code: public boolean hasSlotIsDoubleMetaphoneEqual(final String slotName, final String value) {
          final String slotValue = getSlotValue(slotName);
          return hasSlotNotBlank(slotName) && value != null &&
                  new DoubleMetaphone().isDoubleMetaphoneEqual(slotValue, value);
      }
docs: Checks if a slot is contained in the intent request and has a value which is a
  phonetic sibling of the string given to this method. Double metaphone algorithm
  is optimized for English language and in this case is used to match slot value with
  value given to this method.
  @param slotName name of the slot to look after
  @param value the value
  @return True, if slot value and given value are phonetically equal with Double metaphone algorithm