A striking difference in the transmission system of languages in the two modalities is the existence of two anatomically identical articulators in sign languages: the two hands. Spoken languages have no such potential. On the assumption that the human organism will make full use of its articulatory system, within the relevant modality, in the service of communication, one would expect that both hands would be used in sign language. And indeed they are. But do they function linguistically as two independent articulators in the words of sign language, resulting in a significant phonological difference between the two modalities? Researchers are in agreement that the answer to this question is “no.” The physiological existence of a second articulator generally does not mean that there are two completely independent articulators in the formation of words in the sign language lexicon. Rather, the non-dominant hand (h2) is always in some sense subordinate to other structural elements at the phonological level. This is the most important discovery about the non-dominant hand, as it offers novel insight into the relationship between phonetics, phonology, and the lexicon. What we see is a potential articulator with many degrees of freedom that behaves in a highly restricted way in the words of sign language lexicons.