A Grammar of Sign Language of the Netherlands (NGT)

Reduplication is the repetition of (a part of) a sign, induced by morphology. Many nouns, for instance, may be pluralized by means of reduplication, which involves the addition of extra movements (i.e., syllables) (see also MORPHOLOGY 4.1.1). In Figure 2.68a, the sign person is shown in its singular form, and in Figure 2.68b, it is shown in its plural form (persons). The path movement is repeated in the plural form.

Figure 2.68. Singular (a) and plural (b) form of the noun person.

In Figure 2.69, the singular form of the noun woman is shown, which does not involve a path movement but a secondary movement (index finger and thumb make contact). In the plural form women, it is the secondary movement that is repeated (see also PHONOLOGY 4.1.1). 

Figure 2.69. Singular form of the noun woman (Crasborn et al. 2020).

Reduplication can be accompanied by certain phonetic changes, such as the reduction of movement in the reduplicants (compared to the stem). Two authors noted that signs with multiple syllables in general show a “fading out” effect – as already mentioned in PHONOLOGY 2.2.1 – and this also holds for signs in which the repetition is morphologically induced. Considering the pluralized sign persons again, this is typically a sign in which every repetition is phonetically reduced, compared to the movement of the stem. In other words, in this particular case, the reduction goes hand in hand with a morphological (inflectional) process.