A lemma is a set of related morphological forms. These are related by
orthography in most cases. A lexeme is a meaning realized by a set of
forms. A lexical scatter set is the set of members of a lemma which
realize a particular lexeme.
For example, there is a lemma {water, watered, watering, waters,
watery}. There is a lexeme for a substance which is realized by the
lexical scatter set {water, waters}. There is also a lexeme for the
adding or giving of that substance which is realized by the lexical
scatter set {water, watered, watering, waters}.
This work may have been superseded by the prior marking of texts for
POS, but I think that from a theoretical stand point, parts of speech
are problematic.
Paul R. Hays
Sugiyama Women's Univeristy
Nagoya, Japan