 LFs can be represented as trees, and the terminal nodes of the branches are taken from the lexicon. A lexicon is a repository of lexical items, which need not look like words and they certainly need not correspond to our intuitions about words. Thus, intuitions about a word’s modal profile suggest that it can undergo massive shifts in its orthographic and phonetic properties. It is far less clear that the lexemes retain their identity over shifts of phonological properties. We should be a bit careful, then, about the relationship between words and lexemes: a word may retain its identity while the lexeme it is derived from may not constitute it over time. Fortunately, issues of concerning the diachronic identity of words won’t concern us much here.