From icon to abstraction in sign language: how iconicity shapes the lexicon in the visual modality

语言是一种独特的人类能力，但塑造词汇的力量却鲜为人知。语言学理论的一个中心原则是，词汇是任意的，词和意义仅由约定联系在一起。然而，最近的研究给出了一个更微妙的观点：任意的形式-意义关系与图标和系统关系共存并互补2，3。象似性，形式和意义之间的直接关系，已被证明在语言学习和处理中发挥着重要作用，为我们在世界上的经验提供了具体的基础3 -6。因此，象似性的特点是指抽象概念的能力有限，因此在口语词汇中的范围仍然有限。与口语模态相比，手语的视觉模态具有高度的象似性。在这个项目中，我们探讨了象似性如何限制视觉模态中的形式-意义映射，并为具体和抽象概念塑造词汇。我们利用了这样一个概念，即单词通过具象使用具体概念来发展抽象意义，同时保持与其起源的联系，例如锚的具体和抽象意义共享“防止某物移动“的核心意义8。我们调查手语，聋人社区的自然语言。这些语言在语言组织的各个层面上都是成熟的语言，在它们的词汇中表现出高度的象似性。象似性模式以系统的方式跨越语义域9，10，并且符号经常以表达概念的方式收敛（例如，符号TO-WRITE）。重要的是，手语展示了抽象概念的实例，这些概念来自具体的、图标式的指代。例如，在一个示例中，在德国手语（DGS）中，标志“学校”与标志“写”共享一个标志性的基础（图1）。这表明，标志性符号组共享的元素被利用作为意义多样化的跳板，同时保留一定程度的语义相关性（即共表达过程11）。符号的标志性基础可以在手语之间共享（例如DGS和英国手语（BSL）），并且由于共享的概念表示和共享的模态，说话社区产生的手势也可能具有类似的标志性形式（图1）。通过比较两种不相关的手语（DGS和BSL）中跨语义域的符号的形式和意义，将有可能理解象似性塑造和约束词汇的潜在机制。在德国和英国，非签名者为相同的概念所产生的无声手势与符号进行比较，将揭示共享的认知和/或文化基础的程度，以及这些如何使具体和抽象概念的词汇形式和意义多样化。

Language is a unique human ability, yet the forces shaping vocabulary are little understood. A central tenet of linguistic theory is that the lexicon is arbitrary, with word and meaning related by convention alone1. However, recent research gives a more nuanced view: arbitrary form-meaning relationships co-exist with and complement iconic and systematic relationships2,3. Iconicity, the direct relationship between form and meaning, has been shown to play an important role in language learning and processing, offering a concrete grounding to our experience in the world3-6. As a result, iconicity has been characterised as having a limited capacity to refer to abstract concepts and thus as remaining limited in its scope within the lexicon of spoken languages7. Compared to the spoken modality, the visual modality of sign languages affords a high degree of iconicity. In this project, we explore how iconicity constrains form-meaning mappings in the visual modality and shapes a lexicon for both concrete and abstract concepts.We capitalise on the notion that words develop abstract meaning through the figurative use of concrete concepts while maintaining links to their origin, e.g. the concrete and abstract meaning of anchor share a core meaning of "preventing something from moving"8. We investigate sign languages, the natural languages of deaf communities. These are full-fledged languages on all levels of linguistic organisation and which exhibit a high prevalence of iconicity in their lexicon. Iconicity patterns in systematic ways across semantic domains9,10, and very often signs converge in the way concepts are expressed (e.g. the sign TO-WRITE). Importantly, sign languages exhibit instances of abstract concepts arising from concrete, iconic referents. E.g., in German Sign Language (DGS), the sign SCHOOL shares an iconic base with the sign TO-WRITE (Fig. 1). This suggests that groups of iconic signs share elements that are exploited as a springboard for meaning diversification while retaining some degree of semantic relatedness (i.e. process of colexification11). The iconic base of signs may be shared across sign languages (e.g. DGS and British Sign Language (BSL)), and the gestures produced by speaking communities may also have similar iconic forms (Fig. 1) due to shared conceptual representations and the shared modality. By comparing the form and meaning of signs across semantic domains in two unrelated sign languages (DGS and BSL), it will be possible to understand the underlying mechanisms by which iconicity shapes and constrains a lexicon. Comparing signs with silent gestures produced for the same concepts by non-signers in Germany and the UK will reveal the extent of shared cognitive and/or cultural bases and how these may diversify lexical forms and meanings for concrete and abstract concepts.