LAUSR

Spoken word recognition is central to language, as words link sound, articulation, and spelling to meaning and syntax. Decades of work has yielded consensus that the mechanisms of word recognition can be described as a form of competition among candidates that is tightly coupled to the unfolding speech input (1). However, recent research has pushed beyond the modal listener (monolingual, normal hearing, neurotypical adults) to observe novel profiles of recognition which may help listeners become more flexible (2), for example, by altering the dynamics of word recognition in difficult listening conditions, or keeping options open in case a mistake is made and they must switch to a new interpretation. Villamerial et al. (3) extend this enterprise with a unique group of bilinguals who use both a spoken and a signed language. They offer conclusive evidence for direct interaction between the two languages during recognition (a key issue in multilingualism) and reveal pathways of information processing that may be critical for understanding how listeners flexibly recognize words in challenging circumstances. Words unfold rapidly over time. Consequently, there is a brief period where the input is consistent with many candidates. For instance, the onset of “wizard” (wi-) is consistent with “window,” “wizard,” and “which” (etc.). Decades of research has concluded that modal listeners cope with this by using a form of competition (1). At word onset, multiple candidates are briefly coactivated and compete. Competition is modulated as more input arrives, until, eventually, one candidate remains. These dynamics can be visualized with the visual world paradigm (VWP) (Fig. 1A and ref. 4), as used in ref. 3. This uses eye movements in a simple word recognition task to trace the dynamics of word recognition as processing unfolds over time. Classic results (4) validate that competition is tightly coupled to the unfolding input: Early in recognition, listeners fixate both target words and onset competitors (e.g., “wizard” and “window”), and only later do they consider rhymes (e.g., “lizard”). This framing offers a clear avenue for examining a fundamental issue in bilingualism: Do listeners actively engage both languages during recognition, or are the lexica for each language functionally separate? Seminal studies by Marian and colleagues (see ref. 5 for review) used the VWP to show that words are activated in both languages. For example, when Russian/English bilinguals hear “marka” (stamp), they briefly look at a “marker” before settling on the target, even though the Russian word for “marker” (flomaster) has little overlap with marka. This implies the English word “marker” is active, despite English being irrelevant for the task. Standard models of word recognition argue that bottom-up input obligatorily activates all words consistent with it. The logical consequence of this is that “mark-” should activate both Russian and English words (Fig. 1B) without requiring true cross-talk between the lexica. However, for a speaker of both a spoken and signed language (bimodal bilinguals), this issue is avoided—both languages cannot be activated by the same bottom-up input. For example, the phonemes /v/, /i/, /n/, and /o/ in the Spanish “vino” (wine), are completely unrelated to the manual properties of the sign for“witch” (bruja). Thus, there is no reason to activate “bruja” after hearing “vino” based on input alone. Nonetheless, Villamerial et al. (3) observe such cross-modal activation. This occurs because the sign for “vino” overlaps with “bruja” in its physical characteristics (hand shape and location). Their study thus offers a capstone to a series of studies on this unique population (6, 7), showing that cross-language activation arises even if the bottom-up input cannot support parallel activation. This strongly supports true cross-talk between the lexica (Fig. 1C). While this offers conclusive evidence for interactions across languages, it also reveals a pathway for information flow that may be fundamental to word recognition even in monolinguals: information flow within the lexical level by which words directly activate other words(Fig. 1C, dashed path connecting "vino" and "bruja"). We’ve long known semantic overlap facilitates spreading activation (8), but here we se evidence of word!word spreading activation based on phonological similarity. This appears to challenge the common assumption that word recognition should maximize efficiency. Activating a second lexicon—even when the bottom-up signal does not necessitate it—vastly increases the amount of competition that must be resolved. Indeed, some research is premised on the idea that multilinguals require cognitive resources to effectively suppress activation across languages (9). However, what if this increased competition should be embraced, not avoided? Efficiency is not the only functional goal of word recognition—recognition must also be flexible. All listeners (or signers) face the possibility of perceptual errors. For example, when hearing “lizard,” if