[[analysis-stemmer-tokenfilter]]
=== Stemmer Token Filter

A filter that provides access to (almost) all of the available stemming token
filters through a single unified interface. For example:

[source,js]
--------------------------------------------------
{
    "index" : {
        "analysis" : {
            "analyzer" : {
                "my_analyzer" : {
                    "tokenizer" : "standard",
                    "filter" : ["standard", "lowercase", "my_stemmer"]
                }
            },
            "filter" : {
                "my_stemmer" : {
                    "type" : "stemmer",
                    "name" : "light_german"
                }
            }
        }
    }
}
--------------------------------------------------

The `language`/`name` parameter controls the stemmer with the following
available values (the preferred filters are marked in *bold*):

[horizontal]
Arabic::

http://lucene.apache.org/core/4_9_0/analyzers-common/org/apache/lucene/analysis/ar/ArabicStemmer.html[*`arabic`*]

Armenian::

http://snowball.tartarus.org/algorithms/armenian/stemmer.html[*`armenian`*]

Basque::

http://snowball.tartarus.org/algorithms/basque/stemmer.html[*`basque`*]

Brazilian Portuguese::

http://lucene.apache.org/core/4_9_0/analyzers-common/org/apache/lucene/analysis/br/BrazilianStemmer.html[*`brazilian`*]

Bulgarian::

http://members.unine.ch/jacques.savoy/Papers/BUIR.pdf[*`bulgarian`*]

Catalan::

http://snowball.tartarus.org/algorithms/catalan/stemmer.html[*`catalan`*]

Czech::

http://portal.acm.org/citation.cfm?id=1598600[*`czech`*]

Danish::

http://snowball.tartarus.org/algorithms/danish/stemmer.html[*`danish`*]

Dutch::

http://snowball.tartarus.org/algorithms/dutch/stemmer.html[*`dutch`*],
http://snowball.tartarus.org/algorithms/kraaij_pohlmann/stemmer.html[`dutch_kp`]

English::

http://snowball.tartarus.org/algorithms/porter/stemmer.html[*`english`*],
http://ciir.cs.umass.edu/pubfiles/ir-35.pdf[`light_english`],
http://www.researchgate.net/publication/220433848_How_effective_is_suffixing[`minimal_english`],
http://lucene.apache.org/core/4_9_0/analyzers-common/org/apache/lucene/analysis/en/EnglishPossessiveFilter.html[`possessive_english`],
http://snowball.tartarus.org/algorithms/english/stemmer.html[`porter2`],
http://snowball.tartarus.org/algorithms/lovins/stemmer.html[`lovins`]

Finnish::

http://snowball.tartarus.org/algorithms/finnish/stemmer.html[*`finnish`*],
http://clef.isti.cnr.it/2003/WN_web/22.pdf[`light_finnish`]

French::

http://snowball.tartarus.org/algorithms/french/stemmer.html[`french`],
http://dl.acm.org/citation.cfm?id=1141523[*`light_french`*],
http://dl.acm.org/citation.cfm?id=318984[`minimal_french`]

Galician::

http://bvg.udc.es/recursos_lingua/stemming.jsp[*`galician`*],
http://bvg.udc.es/recursos_lingua/stemming.jsp[`minimal_galician`] (Plural step only)

German::

http://snowball.tartarus.org/algorithms/german/stemmer.html[`german`],
http://snowball.tartarus.org/algorithms/german2/stemmer.html[`german2`],
http://dl.acm.org/citation.cfm?id=1141523[*`light_german`*],
http://members.unine.ch/jacques.savoy/clef/morpho.pdf[`minimal_german`]

Greek::

http://sais.se/mthprize/2007/ntais2007.pdf[*`greek`*]

Hindi::

http://computing.open.ac.uk/Sites/EACLSouthAsia/Papers/p6-Ramanathan.pdf[*`hindi`*]

Hungarian::

http://snowball.tartarus.org/algorithms/hungarian/stemmer.html[*`hungarian`*],
http://dl.acm.org/citation.cfm?id=1141523&dl=ACM&coll=DL&CFID=179095584&CFTOKEN=80067181[`light_hungarian`]

Indonesian::

http://www.illc.uva.nl/Publications/ResearchReports/MoL-2003-02.text.pdf[*`indonesian`*]

Irish::

http://snowball.tartarus.org/otherapps/oregan/intro.html[*`irish`*]

Italian::

http://snowball.tartarus.org/algorithms/italian/stemmer.html[`italian`],
http://www.ercim.eu/publication/ws-proceedings/CLEF2/savoy.pdf[*`light_italian`*]

Kurdish (Sorani)::

http://lucene.apache.org/core/4_9_0/analyzers-common/org/apache/lucene/analysis/ckb/SoraniStemmer.html[*`sorani`*]

Latvian::

http://lucene.apache.org/core/4_9_0/analyzers-common/org/apache/lucene/analysis/lv/LatvianStemmer.html[*`latvian`*]

Norwegian (Bokmål)::

http://snowball.tartarus.org/algorithms/norwegian/stemmer.html[*`norwegian`*],
http://lucene.apache.org/core/4_9_0/analyzers-common/org/apache/lucene/analysis/no/NorwegianLightStemmer.html[*`light_norwegian`*],
http://lucene.apache.org/core/4_9_0/analyzers-common/org/apache/lucene/analysis/no/NorwegianMinimalStemmer.html[`minimal_norwegian`]

Norwegian (Nynorsk)::

http://lucene.apache.org/core/4_9_0/analyzers-common/org/apache/lucene/analysis/no/NorwegianLightStemmer.html[*`light_nynorsk`*],
http://lucene.apache.org/core/4_9_0/analyzers-common/org/apache/lucene/analysis/no/NorwegianMinimalStemmer.html[`minimal_nynorsk`]

Portuguese::

http://snowball.tartarus.org/algorithms/portuguese/stemmer.html[`portuguese`],
http://dl.acm.org/citation.cfm?id=1141523&dl=ACM&coll=DL&CFID=179095584&CFTOKEN=80067181[*`light_portuguese`*],
http://www.inf.ufrgs.br/\~buriol/papers/Orengo_CLEF07.pdf[`minimal_portuguese`],
http://www.inf.ufrgs.br/\~viviane/rslp/index.htm[`portuguese_rslp`]

Romanian::

http://snowball.tartarus.org/algorithms/romanian/stemmer.html[*`romanian`*]

Russian::

http://snowball.tartarus.org/algorithms/russian/stemmer.html[*`russian`*],
http://doc.rero.ch/lm.php?url=1000%2C43%2C4%2C20091209094227-CA%2FDolamic_Ljiljana_-_Indexing_and_Searching_Strategies_for_the_Russian_20091209.pdf[`light_russian`]

Spanish::

http://snowball.tartarus.org/algorithms/spanish/stemmer.html[`spanish`],
http://www.ercim.eu/publication/ws-proceedings/CLEF2/savoy.pdf[*`light_spanish`*]

Swedish::

http://snowball.tartarus.org/algorithms/swedish/stemmer.html[*`swedish`*],
http://clef.isti.cnr.it/2003/WN_web/22.pdf[`light_swedish`]

Turkish::

http://snowball.tartarus.org/algorithms/turkish/stemmer.html[*`turkish`*]

