If a grammar is a formal representation of the linguistic competence of an idealised language user, then it is only natural to consider the lexicon as the formal representation of that part of the competence which contains the mental dictionary. [...] The psychological notion of the lexicon is certainly quite useful, but, still, it is important to keep it apart from the earlier one. Therefore, when talking about the psychological notion, I will use the term "mental lexicon", provided this is not already evident from the context.
- Hoeksma (2004), Pag. 186