The generalizability issue in studying inflectional processing in real time: the potential effects of suffixal characteristics.

For both native speakers and second language (L2) learners, variation in the relative order of acquisition of inflectional morphemes has been shown in the literature. Previous studies employing the simple lexical decision task have also shown effects of suffixal characteristics on word recognition of both derived and inflected words such that some inflectional suffixes trigger whole-word processing while others contribute to decomposition. Additionally, evidence from the masked priming paradigm shows that suffixal characteristics affect the efficiency of morphological decomposition of derived words during early-stage processing. However, very little work has systematically examined the early stages of processing inflected words with different suffixes, leaving our understanding of the factors that impact the early-stage processing of inflected words incomplete at best. We argue that the overwhelming focus on the past tense -ed suffix in previous L2 studies risks exacerbating already serious generalizability issues in the realm of L2 research. Future studies would therefore do well to include and compare a wider range of inflectional suffixes, which may well require looking beyond English. This is essential for the field to make progress toward a more complete understanding of the processing of morphologically complex words.