23. The German lexicon is Wikidata Lexemes

Context

German shipped with four capabilities and no lexicon. Five implemented procedures — charade, semordnilap, word_square, n_plus_7, s_plus_7 — were English-only for want of lexicon.words and lexicon.nouns.

The candidates each carry a licence the core would have had to answer for. igerman98 is GPL-2/3; a Wiktionary dump is CC BY-SA; DeReWo is non-commercial. ADR 0013 already quarantines data licences per distribution, so any of them was possible — but a permissive one costs nothing to prefer.

Decision

Wikidata Lexemes, CC0, vendored in denckring-de-data.

Coverage measured before the decision, not after: 184,040 noun lemmas surviving the single-token filter, and 668,580 distinct written representations across all lexical categories for membership. For comparison, CMUdict carries 135,166 entries.

The 668,580 figure is distinct written representations, not a count of Wikidata form entities. An earlier pass counted 1,399,865 noun forms alone by entity, before deduplication — many German forms share one written string, and membership stores casefolded distinct strings rather than form identifiers. Both numbers are correct measurements of different things; the gap is not lost coverage.

Membership unions every lexical category, not nouns alone: charade and word_square ask "is this a word", and a noun-only oracle rejects singen and rot.

Umlauts and ß are preserved in storage. Casefolding is applied for membership comparison, and casefold() deliberately folds ß to ss there, merging the Swiss and German spellings of one word (e.g. Maßen/Massen) into a single membership entry; the noun list keeps ß as written and is not casefolded. fold_diacritics is a separate, unrelated fold — it is not applied to membership, because collapsing Bär into Bar is a decision ADR 0009 makes a parameter of the procedure, not a property of the lexicon.

Consequences

The generating SPARQL is committed, so the vendored files are reproducible and a diff between versions is readable. CMUdict is not, and this is the better precedent.

CC0 means no attribution or share-alike obligation reaches a user of denckring[de]. LICENSE-WIKIDATA records the provenance anyway, because the project records provenance.

The oracle is broad in the way ADR 0015 described for English: it answers "could this be a German word", and procedures resting on it inherit that.