Consequences of the Now-or-Never bottleneck for signed versus spoken languages.

Signed and spoken languages emerge, change, are acquired, and are processed under distinct perceptual, motor, and memory constraints. Therefore, the Now-or-Never bottleneck has different ramifications for these languages, which are highlighted in this commentary. The extent to which typological differences in linguistic structure can be traced to processing differences provides unique evidence for the claim that structure is processing.