The Bottleneck Hypothesis (Slabakova, 2008(Slabakova, , 2013 proposes that acquiring properties of the functional morphology is the most challenging part of learning a second language. In the experiment presented here, the predictions of this hypothesis are tested in the L2 English of Norwegian native speakers. Two constructions are investigated that do not match in English and Norwegian: One involving functional morphology, Subject-Verb (SV) agreement, which is obligatory in the L2 but non-existent in the L1, and one involving syntax, Verb-Second (V2) word order, which is obligatory in the L1, but restricted to specific contexts in the L2. The results of an acceptability judgement task indicate that the participants struggled more with identifying ungrammatical SV agreement than ungrammatical word order. We conclude that the findings lend tentative support to the Bottleneck Hypothesis.

In this study, we investigated crosslinguistic influence (CLI) at developmental stages of third language (L3) acquisition of English by Russian-Norwegian children (N = 31). We tested seven linguistic properties within three linguistic modules (morphology, syntax and syntax-semantics). We compared the L3 learners to Norwegian (N = 90) and Russian (N = 74) second language (L2) learners of English. We predicted simultaneous facilitative and non-facilitative CLI in the L3 group within all modules, as the previously acquired languages offered conflicting options. Our predictions were partly supported. On one property, the L3 learners were different from both L2 groups, which is in line with cumulative CLI from both previously acquired languages. On four conditions, the L3 learners performed like the more accurate L2 group, indicating facilitative influence. On two conditions, all groups performed alike, showing high rates of accuracy. Taken together, the results indicate that CLI obtains on a property-byproperty basis, with none of the L1s being the sole or primary source of CLI. Finally, we found CLI in all linguistic domains, but the developmental slopes for the properties were not equal, which suggests that factors such as complexity and saliency needs to be taken into account when we compare CLI.

Over the last two decades, the question of to which linguistic cues learners pay attention when they decode a new language has been subject to controversy in the field of third language (L3) acquisition. In this article, we present an artificial language learning experiment that investigated how lexical and syntactic similarities between an artificial L3 and preexisting grammars impact crosslinguistic influence at the very beginning of the acquisition process. We exposed four groups of 30 Norwegian-English bilinguals each to one of four L3s and gave them training in that L3. The participants gave forced-choice acceptability judgments on pairs of nonsubject-initial declarative clauses that differed in word order, one grammatical in English, the other grammatical in Norwegian. The participants had not been exposed to nonsubject-initial declaratives during the exposure and training phases to avoid confounds with learning. The results showed that both lexical and syntactic similarities affect crosslinguistic influence. We discuss this result considering contemporary accounts of L3 acquisition.