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NorwegianSnowballStemmer

Norwegian Bokmål stemming by the Snowball algorithm.

public static class NorwegianSnowballStemmer

Example — a noun, its plural and its definite plural, collapsed onto one key.

using Lodestar.Text.Stemming;

string singular = NorwegianSnowballStemmer.Stem("gutt");  // => gutt
string definite = NorwegianSnowballStemmer.Stem("gutten");  // => gutt
string plural = NorwegianSnowballStemmer.Stem("guttene");  // => gutt
string genitive = NorwegianSnowballStemmer.Stem("guttenes");  // => gutt

Remarks — This is Bokmål, and only Bokmål. The reference is nltk's norwegian, which implements the Bokmål algorithm; Nynorsk has no oracle here and is out of scope for the same reason Turkish is. A Nynorsk word will return something, and that something is noise.

Norwegian is built like the Swedish stemmer next door: three steps, all of them searching R1, with no R2 and no RV region. Two things beyond that are worth knowing.

The region is part of the search, not a test after it. Each step looks for the longest suffix that lies in R1 — not the longest suffix, checked against R1 afterwards. This is the rule the German stemmer states the other way round, and the one most likely to be got wrong by hand.

One group of endings is rewritten rather than stripped. ert and erte both become er, so servert and serverte meet at server instead of at two different keys.

æ, å and ø are letters of the alphabet rather than accented forms. All three count as vowels, and all three come back exactly as they went in — hånd and hånden stem to hånd, not to hand.

R1 is floored at three characters as in German, which is what stops short words from being trimmed to nothing — the job RV does in the Romance languages. år and året come back whole for that reason, and so does boks, whose s follows a k that is itself after a vowel.

Reference behaviour is nltk.stem.snowball.SnowballStemmer("norwegian"), matched over 244 words.

Applies to — net10.0, netstandard2.0.

See also — the stemming index.

Members

Member	What it does
NorwegianSnowballStemmer.Stem	The Snowball stem of one Norwegian word.