In the previous chapter we have seen that fossilization as a theoretical construct has been interpreted in a variety of different ways. The lack of uniformity in the general understanding of the notion, as a consequence, has led researchers, over the years, to apply the term to a wide array of learner behaviors. In this chapter, I will first provide a quick sketch of the putative behavioral reflexes and causal variables of fossilization, and then offer a more in-depth view on a selection of sample explanations. After that, I will highlight and discuss two what I believe are primary determinants of lack of ability to learn a second language.

An Overview

Below is a list of what researchers have recognized as behavioral reflexes of fossilization (cf. Selinker & Han, 2001; Han, 2003):

• • Backsliding (e.g., R. Ellis, 1985; Schachter, 1988; Selinker, 1972).

• • Stabilized errors (e.g., Schumann, 1978a).

• • Persistent non-target-like performance (e.g., Mukattash, 1986).

• • Learning plateau (e.g., Flynn & O'Neil, 1988).

• • Typical error (Kellerman, 1989).

• • Low proficiency (e.g. Thep-Ackrapong, 1990).

• • De-acceleration of the learning process (e.g., Washburn, 1991).

• • Ingrained errors (Valette, 1991).

• • Systematic use of erroneous forms (Allwight & Bailey, 1991).

• • Variable outcomes (Perdue, 1993).

• • Cessation of learning (e.g., Odlin, 1993).

• • Structural persistence (e.g., Schouten, 1996).

• • Errors that are impervious to negative evidence (Lin & Hedgcock, 1996).

• • Random use of grammatical and ungrammatical structures (Schachter, 1996).

• • Habitual errors (SLART-L, 1997).

• • Errors made by advanced learners (e.g., Selinker & Mascia, 1999).

• • Long-lasting free variation (R. Ellis, 1999).

• • Persistent difficulty (Hawkins, 2000).

• • Ultimate attainment (passim the SLA literature).

• • Inability to fully master target language features (passim the SLA literature).

As the above list indicates, over the years the term 'fossilization' has come to be associated with a wide array of learner behaviors.