This article presents a theoretical review of and methodological guidelines for the study of two key notions in second language acquisition research, complexity and difficulty. The term "complexity" has gained considerable currency over the past decades and has taken on a wide range of meanings. We argue for a more restricted…

In this Methods Showcase Article, we illustrate mixed-effects modeling with a multinomial dependent variable as a means of explaining complexities in language. We model data on future-time reference in second language Spanish, which consists of a nominal dependent variable that has three levels, measured over 73 participants. We offer step-by-step…

This systematic review surveyed research on the associations between sleep and the memory processes involved in word learning in infancy. We found only 16 studies that addressed this topic directly, identifying associations between infant sleep and the memory processes, the identification of word forms in running speech, and the stabilization and…

In this study, we assessed metacognition in nonnative language speech perception and production. Spanish novice learners of French identified and produced the French vowel contrast /ø/--/oe/ and, on each trial, rated their confidence in their responses. Participants' confidence in perception predicted their identification accuracy, suggesting that…

This article provides a conceptual review of the principles of input spacing as they might relate specifically to oral task repetition research and presents some of the common methodological considerations from the broader input spacing literature. The specific considerations discussed include the interaction between intersession intervals and…

A large number of children are exposed to more than one language. One well-established method of assessing early vocabulary development in monolingual children is parent report; however, its use in bilingual/multilingual contexts is less established and brings unique challenges. In this methodological scoping review, we reviewed studies of early…

This study reports on strategies to indicate plural referents in hearing learners of Sign Language of the Netherlands. This is the first explorative study that focuses on L2 expressions of plurality in a sign language. Using data from two datasets, I examined when learners start to express plural and which strategies they apply, and I noted…

This study is the first to explore microdevelopment in sociolinguistic evaluative judgments of standard German and Austro-Bavarian dialect by adult second language learners of German by using dense time serial measurements. Intensive longitudinal data (10 observations per participant) were collected from four learners at approximately weekly…

To acquire language, learners have to map the language onto the environment, but languages vary as to how much information they include to constrain how a sentence relates to the world. We investigated the conditions under which information within the language and the environment is combined for learning. In a cross-situational artificial language…

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…

A strong predictor of children's language is performance on non-word repetition (NWR) tasks. However, the basis of this relationship remains unknown. Some suggest that NWR tasks measure phonological working memory, which then affects language growth. Others argue that children's knowledge of language/language experience affects NWR performance. A…

Second language (L2) grammar learning is difficult. Two frameworks--the psycholinguistic lexical bottleneck hypothesis and the neurocognitive declarative/procedural model--predict that faster L2 lexical processing should facilitate L2 incidental grammar learning. We tested these predictions in a pretest-posttest syntactic adaptation study of…

The young universal listener is an established concept in psycholinguistics. However, it is unclear what abilities universal perception entails and at what age it exists. This article aims to motivate rethinking about what it means to be a universal listener. Early and recent studies on infant speech acquisition are reviewed, considered in the…

This study examined the influence of cognate status and language distance on simultaneous bilingual children's vocabulary acquisition. It aimed to tease apart effects of word-level similarities and language-level similarities, while also exploring the role of individual-level variation in age, exposure, and nontarget language proficiency. Children…

Word segmentation is a crucial step in children's vocabulary learning. While computational models of word segmentation can capture infants' performance in small-scale artificial tasks, the examination of early word segmentation in naturalistic settings has been limited by the lack of measures that can relate models' performance to developmental…