Knowledge of Language Transfers From Speech to Sign: Evidence From Doubling.

Does knowledge of language transfer across language modalities? For example, can speakers who have had no sign language experience spontaneously project grammatical principles of English to American Sign Language (ASL) signs? To address this question, here, we explore a grammatical illusion. Using spoken language, we first show that a single word with doubling (e.g., trafraf) can elicit conflicting linguistic responses, depending on the level of linguistic analysis (phonology vs. morphology). We next show that speakers with no command of a sign language extend these same principles to novel ASL signs. Remarkably, the morphological analysis of ASL signs depends on the morphology of participants' spoken language. Speakers of Malayalam (a language with rich reduplicative morphology) prefer XX signs when doubling signals morphological plurality, whereas no such preference is seen in speakers of Mandarin (a language with no productive plural morphology). Our conclusions open up the possibility that some linguistic principles are amodal and abstract.

ANCHORING is amodal: Evidence from a signed language.

Across languages, certain linguistic forms are systematically preferred to others (e.g. bla > lba). But whether these preferences concern abstract constraints on language structure, generally, or whether these restrictions only apply to speech is unknown. To address this question, here we ask whether linguistic constraints previously identified in spoken languages apply to signs. One such constraint, ANCHORING, restricts the structure of reduplicated forms (AB → ABB, not ABA). In two experiments, native ASL signers rated the acceptability of novel reduplicated forms that either violated ANCHORING (ABA) or obeyed it (ABB). In Experiment 1, signers made a forced choice between ABB and ABA forms; in Experiment 2, signers rated signs individually. Results showed that signers prefer signs that obey ANCHORING over ANCHORING violations (ABB > ABA). These findings show for the first time that ANCHORING is operative in ASL signers. These results suggest that some linguistic constraints are amodal, applying to both speech and signs.

The double identity of doubling: Evidence for the phonology-morphology split.

Duality of patterning, is, by hypothesis, a universal design feature of language. Every language constructs words from meaningful units (morphemes), which, in turn, are comprised of meaningless phonological elements (e.g., segments, syllables). But whether the language faculty does, in fact, include a separate morphological level, distinct from the phonology, is a matter of controversy. To elucidate the role of morphology, here we ask whether morphological forms are constrained by putatively universal combinatorial principles, distinct from those applying to phonological patterns. Our research exploits the structural ambiguity of doubling. Doubling (e.g., trafraf) is open to two competing interpretations-as either a purely phonological form, or as a complex morphological structure that is systematically linked to meaning (e.g., trafraf is the diminutive of traf). Our experiments show that responses to doubling (trafraf) shift radically, depending on its level of analysis. Viewed as a meaningless phonological form, doubling is dispreferred irrespective of its kind (i.e., trafraf is as bad as traftaf, even though the latter violates a morphological constraint on contiguity). But once doubling is systematically linked to meaning (i.e., as a morphological structure), the doubling dislike shifts into a reliable preference, and an additional constraint on its contiguity arises (i.e., trafraf>traftaf). Remarkably, the dissociation between morphological and phonological doubling emerges regardless of whether morphological reduplication is abundant in participants' language (in Hebrew) or relatively rare (in English). These results suggest the existence of distinct linguistic constraints that preferentially target the morphological vs. phonological levels. We discuss various explanations for the origins of these restrictions.

The double identity of linguistic doubling.

Does knowledge of language consist of abstract principles, or is it fully embodied in the sensorimotor system? To address this question, we investigate the double identity of doubling (e.g., slaflaf, or generally, XX; where X stands for a phonological constituent). Across languages, doubling is known to elicit conflicting preferences at different levels of linguistic analysis (phonology vs. morphology). Here, we show that these preferences are active in the brains of individual speakers, and they are demonstrably distinct from sensorimotor pressures. We first demonstrate that doubling in novel English words elicits divergent percepts: Viewed as meaningless (phonological) forms, doubling is disliked (e.g., slaflaf < slafmak), but once doubling in form is systematically linked to meaning (e.g., slaf = ball, slaflaf = balls), the doubling aversion shifts into a reliable (morphological) preference. We next show that sign-naive speakers spontaneously project these principles to novel signs in American Sign Language, and their capacity to do so depends on the structure of their spoken language (English vs. Hebrew). These results demonstrate that linguistic preferences doubly dissociate from sensorimotor demands: A single stimulus can elicit diverse percepts, yet these percepts are invariant across stimulus modality--for speech and signs. These conclusions are in line with the possibility that some linguistic principles are abstract, and they apply broadly across language modality.