Blocking concerns the effect of second language (L2) speakers’ prior language experience on learning linguistic cues that express one idea (e.g. past tense) in multiple ways (e.g. adverbial cues and verbal morphology). Previous research provides evidence for long-term blocking, whereby cross-linguistic differences lead L2 speakers to rely on an L1 cue to the disadvantage of a new L2 cue, as well as short-term blocking, whereby the initial learning of one cue makes the later learning of another cue more difficult (Ellis & Sagarra, 2010). However, studies have not investigated instructed L2 speakers’ acquisition of cues that cannot co-occur within a sentence.
In the present study, beginning L2 German speakers (N = 20) learned the present perfect tense. Unlike English, in which the auxiliary verb is always have, German uses two different auxiliary verbs, haben “have” or sein “be”, with any given verb taking only one auxiliary, as in (1) and (2).
Using a pretest, posttest, delayed posttest design, three experimental groups completed a meaning-based output treatment that differed only in the order of auxiliary introduction: haben initial, sein initial, and both auxiliaries simultaneously. In all three groups, long-term blocking from participants’ L1 English would promote haben, which was reinforced by short-term blocking among the haben initial group and countered in the sein initial group. Results from a fill-in-the-blank test showed that the haben and sein initial groups were more accurate on whichever auxiliary they learned first, providing evidence for short-term blocking. The haben and both, but not the sein, groups, favored haben over sein, providing evidence for long-term blocking. Thus, short-term blocking can deemphasize L1 patterns and instead draw L2 speakers’ attention to a novel L2 cue, promoting its acquisition.