Grammar, how lexemes should be used in relation to other lexemes. Example
String inputs as values should link each word to a lexeme and it's form/sense
Modeling abbreviations? Abbreviations don't seem to be lexemes...
Research double inverse property relationships for RDF. Relationships should not be one-way. See how graph databases handle inverse properties. Can a property cover a single double relationship?
Items for articles
Text fragment references?
Requirement to pass down "has parts of the class" property and make it more specific for subclasses and "has part" for instances
Subclasses should always have a differentiating property between their other subclass mates?