“…Previous studies suggest that the effects of PAL may be affected by factors such as the direction (i.e., receptive or productive) and frequency of retrieval, type of elaboration (i.e., semantic or structural), type of information provided (e.g., fi rst language [L1] translations, context, or pictures), type and timing of feedback, and interference as well as item-related factors such as word length, parts of speech, pronounceability, concept imageability, and concept frequency (for reviews, see Laufer, 2012 ;Nation, 2001 ). Research also shows that in PAL, spaced learning, which involves spacing between repetitions of a given item, yields superior retention than does massed learning, which does not involve any spacing; this phenomenon is known as the spacing effect (e.g., Cepeda, Pashler, Vul, Wixted, & Rohrer, 2006 ;Cull, 2000 ;Cull, Shaughnessy, & Zechmeister, 1996 ;Karpicke & Bauernschmidt, 2011 ;Karpicke & Roediger, 2007 ;Logan & Balota, 2008 ;Maddox, Balota, Coane, & Duchek, 2011 ).…”