Introduction and Research Goals

Almost 20 years ago, Harley (1998: 27) lamented the fact that no explanation had been provided as to why in school settings ‘the additional time associated with an early headstart has not been found to provide more substantial long-term proficiency benefits’. Despite the abundance of critical period studies, maturational state studies and ultimate attainment studies that have been carried out in the meantime (see, e.g. García Lecumberri & Gallardo, 2003; Larson-Hall, 2008; Moyer, 2004; Muñoz, 2003, 2006a, 2008, 2011; for reviews see Lambelet & Berthele, 2015; Muñoz & Singleton, 2011; Singleton, 2005; Singleton & Ryan, 2004), there are still unexplored issues regarding the amount and type of input needed for earlier starters in a school context to surpass later starters and to be able to retain their learning advantages in the long term. In the light of the fact that, since the 1990s, numerous educational authorities in Europe have brought forward the starting age of language instruction in elementary schools, it seems to be particularly important at this point to further analyse the magnitude of the effects of initial age of learning on the end state in a foreign language (FL) classroom.

The introduction of early FLs has given rise to several educational, political and research questions, most of them related to the teaching approach in primary school and the apparent lack of learning success of early classroom learners (ECLs) compared to late classroom learners (LCLs), who, in the past, used to start learning the FL at the beginning of secondary school. In view of their rather unimpressive impact, early FL programmes are currently under scrutiny in Europe (and elsewhere in the world), and the question has arisen as to what extent these investigations relate to what crucially influences the absolute abilities of classroom learners at the end of mandatory school time, and, importantly, how we can exploit an earlier starting age more effectively – a topic that is, at present, still not understood very well.