Is there an ideal time window for language acquisition after which nativelike representation and processing are unattainable? Although this question has been heavily debated, no consensus has been reached. Here, we present evidence for a sensitive period in language development and show that it is specific to grammar. We conducted a masked priming task with a group of Turkish-German bilinguals and examined age of acquisition (AoA) effects on the processing of complex words. We compared a subtle but meaningful linguistic contrast, that between grammatical inflection and lexical-based derivation. The results showed a highly selective AoA effect on inflectional (but not derivational) priming. In addition, the effect displayed a discontinuity indicative of a sensitive period: Priming from inflected forms was nativelike when acquisition started before the age of 5 but declined with increasing AoA. We conclude that the acquisition of morphological rules expressing morphosyntactic properties is constrained by maturational factors.

The current study investigates to what extent masked morphological priming is modulated by language-particular properties, specifically by its writing system. We present results from two masked priming experiments investigating the processing of complex Japanese words written in less common (moraic) scripts. In Experiment 1, participants performed lexical decisions on target verbs; these were preceded by primes which were either (i) a past-tense form of the same verb, (ii) a stem-related form with the epenthetic vowel -i, (iii) a semantically-related form, and (iv) a phonologically-related form. Significant priming effects were obtained for prime types (i), (ii), and (iii), but not for (iv). This pattern of results differs from previous findings on languages with alphabetic scripts, which found reliable masked priming effects for morphologically related prime/target pairs of type (i), but not for non-affixal and semantically-related primes of types (ii), and (iii). In Experiment 2, we measured priming effects for prime/target pairs which are neither morphologically, semantically, phonologically nor - as presented in their moraic scripts—orthographically related, but which—in their commonly written form—share the same kanji, which are logograms adopted from Chinese. The results showed a significant priming effect, with faster lexical-decision times for kanji-related prime/target pairs relative to unrelated ones. We conclude that affix-stripping is insufficient to account for masked morphological priming effects across languages, but that language-particular properties (in the case of Japanese, the writing system) affect the processing of (morphologically) complex words.

The present study investigates to what extent morphological priming varies across different groups of native speakers of a language. In two masked-priming experiments, we investigate the processing of morphologically complex Turkish words in Turkish heritage speakers raised and living in Germany. Materials and experimental design were based on Kırkıcı and Clahsen’s (2013) study on morphological processing in Turkish native speakers and L2 learners, allowing for direct comparisons between the three groups. Experiment 1 investigated priming effects for morphologically related prime-target pairs. Heritage speakers showed a similar pattern of results as the L1 comparison group, with significant priming effects for prime-target pairs with inflected primes (e.g. ‘sorar-sor’ asks-ask) as well as for prime-target pairs with derived primes (e.g. ‘sağlık-sağ’ health-healthy). In Experiment 2, we measured priming effects for prime-target pairs which were semantically and morphologically unrelated, but only related with regard to orthographic overlap (e.g. ‘devre-dev’ period-giant). Unlike both L1 speakers raised in Turkey and highly proficient L2 learners, heritage speakers also showed significant priming effects in this condition. Our results suggest that heritage speakers differ from both native speakers and L2 learners in that they rely more on (orthographic) surface form properties of the stimulus during early stages of word recognition, at the expense of morphological decomposition.

We report the results from an eye-movement monitoring study investigating how native and non-native speakers of English process temporarily ambiguous sentences such as While the gentleman was eating the burgers were still being reheated in the microwave, in which an initially plausible direct-object analysis is first ruled out by a syntactic disambiguation (were) and also later on by semantic information (being reheated). Both participant groups showed garden-path effects at the syntactic disambiguation, with native speakers showing significantly stronger effects of ambiguity than non-native speakers in later eye-movement measures but equally strong effects in first-pass reading times. Ambiguity effects at the semantic disambiguation and in participants’ end-of-trial responses revealed that for both participant groups, the incorrect direct-object analysis was frequently maintained beyond the syntactic disambiguation. The non-native group showed weaker reanalysis effects at the syntactic disambiguation and was more likely to misinterpret the experimental sentences than the native group. Our results suggest that native language (L1) and non-native language (L2) parsing are similar with regard to sensitivity to syntactic and semantic error signals, but different with regard to processes of reanalysis.