Lexical bias
Challenges the linear sequence of the proposed stages in Levelt model;
More frequent or contextually salient words may be selected more readily, violating the sequentiality
Phonemic switching
when tempting people to make errors, 30% of errors are real words but only 10% non-words
= Lexical bias
Main problem for serial model
Lexical bias means a later phase is affecting an earlier stage, whereas lexical selection should be finished by the time phonological encodings are happening