Current views about language are dominated by the idea of arbitrary connections between linguistic form and meaning. However, if we look beyond the more familiar Indo-European languages and also include both spoken and signed language modalities, we find that motivated, iconic form-meaning mappings are, in fact, pervasive in language. In this paper, we review the different types of iconic mappings that characterize languages in both modalities, including the predominantly visually iconic mappings found in signed languages. Having shown that iconic mapping are present across languages, we then proceed to review evidence showing that language users (signers and speakers) exploit iconicity in language processing and language acquisition. While not discounting the presence and importance of arbitrariness in language, we put forward the idea that iconicity need also be recognized as a general property of language, which may serve the function of reducing the gap between linguistic form and conceptual representation to allow the language system to "hook up" to motor, perceptual, and affective experience. Since everyone perceives the world in the same way, there should be only one human language if properties of objects could in any way (i.e., by “natural” connection) determine the names given them. The persuasive force of this argument, and its far-reaching impact, is not difficult to fathom. Today, no one would subscribe to the idea of an actual “natural” connection between linguistic signs and their denotata. The idea that each object could have an inherently “correct” name known from the object itself strikes us as antiquated and arcane. Language is understood to be a system of conventional symbols shared by a community of users. Users of English must agree about the meaning of /haus/, and this knowledge must be passed on from generation to generation. We can see the stamp of conventionalization even in the case of onomatopoeia, i.e., words like buzz or meow , which imitate sounds in the real world (usually made by objects or animals). In this paper, we argue that the preoccupation with arbitrariness in language has eclipsed a proper acknowledgment of non-arbitrary, i.e., iconic and motivated form-meaning mappings in language. When we widen the scope of linguistic inquiry to include larger expanses of the globe, beyond Indo-European languages (and thus more diverse linguistic structures), as well as language in both modalities (spoken and signed), it is clear that many languages in fact make widespread and systematic use of non-arbitrary form-meaning mappings. In the Section “Iconicity in Languages: Is it Really There?,” we show that regular correspondences between form and meaning exist across both spoken and signed language modalities, motivated by perceptuo-motor properties of real-world experiences. We use iconicity as a blanket term for a broad range of phenomena, including what has been referred to in the literature as sound-symbolism , mimetics , ideophones , and iconicity . It is our view that these different phenomena (discussed below), while varying in amount and degree, all have in common some non-arbitrary, iconic mapping between form and meaning. Most signs, in fact, exhibit both iconic and arbitrary features, and the degree of iconicity or arbitrariness ascribed to individual signs is best understood as a continuum. Examples of iconic and non-iconic signs in British Sign Language (BSL) are given in Figures 1 A–D below. The iconic sign for cry (in Figure 1 A) is made with two extended index fingers (handshape), which move in an alternating pattern downward from the eyes (movement) on the signer's face (location). The sign visually depicts the path of tears as they fall. Moreover, the authors found a slight processing advantage for Japanese words paired with an antonym translation equivalent, which indicates that the effect may hold within conceptual/semantic domains. These findings suggest that sound-symbolic mappings are not arbitrary and language-specific, but rather reflect some more general phenomenon which extends cross-linguistically. Iconic mappings in spoken languages further seem to be more resistant to regular sound changes. Overall, considering judgments, there is clear evidence that speakers are sensitive to iconic form-meaning mappings. However, judgments are a rather indirect measure of language use, being off-line and susceptible to metacognitive strategies. More critical evidence for humans’ sensitivity to iconic mapping must come from on-line studies of language processing that show that iconicity affects lexical processes. To date, there have been only a few experiments addressing the potential impact of iconicity in spoken language processing. This first processing study provides evidence that a more transparent mapping between meaning and form can aid language processing. In a replication of the ASL study, Vinson et al. (submitted) likewise found that BSL signers’ responses in picture-sign matching were faster when the iconic property of a sign appeared saliently in the picture, while non-signers showed no benefit in matching such pictures to English words (replicating Thompson et al., 2009 in a historically unrelated sign language). The Vinson et al. ( 2008 ) found that sign errors produced during a longitudinal study of four deaf children (from as early as 8 months and continuing to as late as 17 months) did not tend However, in contrast to a “gesture-first” evolutionary path into human language, we take the position that both manual and vocal gesture would be necessary as a precursor to our developed language systems. Articulations in both channels provide iconic mappings that would allow the building up of a symbolic system on the scaffolding of analog relations between representational forms and the world. A “gesture-first” model of language evolution is saddled with the burden of explaining the transition from manual to vocal articulation.