Reduplication, also known as doubling or productive repetition, involves copying either a whole or a part of a prosodic word, resulting in a shift in semantic meaning, whether compositional or idiomatic (Inkelas & Zoll 2005, Stolz 2011). Many spoken languages employ reduplication for various linguistic functions, including indicating plurality, aspect, distributivity, adverbials, adjectival intensification, and derivational morphology. For example, in Walpiri, the term kamina 'girl' is reduplicated as kamina kamina 'girls,' while in French Creole, salé 'salty' is reduplicated as sa(lé)-salé 'very salty' (Kouwenberg & LaCharité 2003). I will begin with a preliminary introduction to the general discussions surrounding reduplication and then discuss its manifestation in sign languages, which have been analyzed through several different approaches regarding its classification and denotation. In sign languages, reduplication processes closely parallel those found in spoken languages, encompassing features like plurality (e.g., "BOOK" becomes "BOOK-pl" [although this has been challenged (Becker & Hochgesang 2018)]), aspect (e.g., "EAT" to "EAT-continuous"), and derivational morphology (e.g., "SIT" to "CHAIR"; Klima & Bellugi 1978, Fischer 1972, Supalla & Newport 1978). Nonetheless, some notable distinctions exist, such as the frequent use of triplication in sign languages (Kimmelman 2018) and the omission of the reduplicative feature in signed adjectival intensification in American Sign Language (ASL). It becomes evident that reduplication in sign languages differs fundamentally from that in spoken languages, and I propose an experimental paradigm to assess the grammatical productivity of object-nominalizing reduplication in ASL. It is clear that further experimental and typological studies are essential to identify the key distinctions in reduplication that may be attributed to differences in modality, and this in turn will contribute to theories of language emergence and change.