Hello,

Like Wikipedia Double Metaphone description say (http://en.wikipedia.org/wiki/Double_Metaphone#Double_Metaphone)
"
It is called "Double" because it can return both a primary and a secondary code for a string;
For example, encoding the name "Smith" yields

• a primary code of SM0
• and a secondary code of XMT,
  while the name "Schmidt" yields a primary code of XMT and a secondary code of SMT--both have XMT in common.
  "

In https://github.com/elasticsearch/elasticsearch/blob/master/modules/elasticsearch/src/main/java/org/elasticsearch/index/analysis/phonetic/PhoneticFilter.java

The PhoneticFilter only use only the primary code but not the secondary code

For using the secondary you have to use doubleMetaphone(String value, boolean alternate)
with alternate=false for secondary code
cf http://commons.apache.org/codec/api-release/org/apache/commons/codec/language/DoubleMetaphone.html

The question is how to use this seconday code ?

• May be like a synonym way ?

Best regards

Jérome