elasticsearch/docs/plugins/analysis-phonetic.asciidoc

[[analysis-phonetic]]
=== Phonetic analysis plugin

The Phonetic Analysis plugin provides token filters which convert tokens to
their phonetic representation using Soundex, Metaphone, and a variety of other
algorithms.

:plugin_name: analysis-phonetic
include::install_remove.asciidoc[]


[[analysis-phonetic-token-filter]]
==== `phonetic` token filter

The `phonetic` token filter takes the following settings:

`encoder`::

    Which phonetic encoder to use. Accepts `metaphone` (default),
    `double_metaphone`, `soundex`, `refined_soundex`, `caverphone1`,
    `caverphone2`, `cologne`, `nysiis`, `koelnerphonetik`, `haasephonetik`,
    `beider_morse`, `daitch_mokotoff`.

`replace`::

    Whether or not the original token should be replaced by the phonetic
    token. Accepts `true` (default) and `false`. Not supported by
    `beider_morse` encoding.

[source,console]
--------------------------------------------------
PUT phonetic_sample
{
  "settings": {
    "index": {
      "analysis": {
        "analyzer": {
          "my_analyzer": {
            "tokenizer": "standard",
            "filter": [
              "lowercase",
              "my_metaphone"
            ]
          }
        },
        "filter": {
          "my_metaphone": {
            "type": "phonetic",
            "encoder": "metaphone",
            "replace": false
          }
        }
      }
    }
  }
}

GET phonetic_sample/_analyze
{
  "analyzer": "my_analyzer",
  "text": "Joe Bloggs" <1>
}
--------------------------------------------------

<1> Returns: `J`, `joe`, `BLKS`, `bloggs`

It is important to note that `"replace": false` can lead to unexpected behavior since
the original and the phonetically analyzed version are both kept at the same token position.
Some queries handle these stacked tokens in special ways. For example, the fuzzy `match`
query does not apply {ref}/common-options.html#fuzziness[fuzziness] to stacked synonym tokens.
This can lead to issues that are difficult to diagnose and reason about. For this reason, it
is often beneficial to use separate fields for analysis with and without phonetic filtering.
That way searches can be run against both fields with differing boosts and trade-offs (e.g.
only run a fuzzy `match` query on the original text field, but not on the phonetic version).

[discrete]
===== Double metaphone settings

If the `double_metaphone` encoder is used, then this additional setting is
supported:

`max_code_len`::

    The maximum length of the emitted metaphone token. Defaults to `4`.

[discrete]
===== Beider Morse settings

If the `beider_morse` encoder is used, then these additional settings are
supported:

`rule_type`::

    Whether matching should be `exact` or `approx` (default).

`name_type`::

    Whether names are `ashkenazi`, `sephardic`, or `generic` (default).

`languageset`::

    An array of languages to check. If not specified, then the language will
    be guessed. Accepts: `any`, `common`, `cyrillic`, `english`, `french`,
    `german`, `hebrew`, `hungarian`, `polish`, `romanian`, `russian`,
    `spanish`.