Current idea: lemma (etymological form, what the frequency sink uses, e.g. 付く and 合う) -> dictionary form (full kanji spelling, if there, basically a lemma variant, might even be multiple lemmas combined e.g. 付き合う) -> lookup form (deconjugated, may be in kana, even partially, e.g. 付きあう) -> surface form (conjugated, e.g. 付きあわない)
Current idea: lemma (etymological form, what the frequency sink uses, e.g. 付く and 合う) -> dictionary form (full kanji spelling, if there, basically a lemma variant, might even be multiple lemmas combined e.g. 付き合う) -> lookup form (deconjugated, may be in kana, even partially, e.g. 付きあう) -> surface form (conjugated, e.g. 付きあわない)