5 A note on typological variation across sign languages
At the outset of this paper, I have already pointed out that striking similarities have been found across unrelated sign languages when it comes to the expression of sentential negation. In fact, all sign languages studied to date employ manual and non-manual markers. The existence of such a basic common pattern, however, does not imply that all sign languages are typologically the same. Actually, on closer inspection, it turns out that the attested similarities are only superficial ones. In this section, I will provide data from some other sign languages that suggest that the analysis that I offered above for DGS may not be generally applicable to sign languages.
Let us first look at sign languages that seem to pattern with DGS in the expression of negation. In Indopakistani Sign Language (IPSL), just as in DGS, the basic word order is SOV and the manual Neg sign follows the verb. In (28a), the headshake extends over the manual Neg sign and the verb. The manual negator, however, is optional, as can be seen in (28b), where only the verb is accompanied by a headshake (Zeshan 2000: 114).
Similarly, in Catalan Sign Language (Llengua de Signes Catalana: LSC), the manual sign is optional and follows the verb. In contrast to DGS, however, it is possible for the headshake to accompany the manual Neg sign only; compare (29a) with the ungrammatical DGS example (20a). In the absence of not, LSC patterns with DGS in that the headshake may extend over the verb sign only (29b). Optionally, it may spread over the direct object– just as in DGS (Pfau and Quer 2007: 131).
Example (29b) implies that the headshake is a featural affix that attaches to the predicate in the way sketched in (18). The grammaticality of (29a), however, suggests that in LSC, the featural affix may also combine with the manual Neg sign, which presumably is not lexically specified for this non-manual feature. Still, headshake is prosodic in LSC; it is suprasegmental and it is capable of spreading over well-defined domains.
Sign languages which employ an optional manual negative element and an obligatory non-manual marker are referred to as non-manual dominant sign languages by Zeshan (2006a). Sign languages of this type contrast as a group with manual dominant sign languages, in which the use of a manual negator is obligatory. Italian Sign Language (Lingua Italiana dei Segni: LIS) is a language of the latter type. Consider the examples in (30). In (30a), just as in (29a), the headshake accompanies only the sentence-final Neg sign. In striking contrast to LSC and DGS, however, in LIS, the manual Neg sign is obligatory. Hence, (30b) is ungrammatical irrespective of the scope of the non-manual marker (Geraci 2005). Moreover, even in the presence of the manual sign not, the headshake cannot spread; it is confined to the manual negative sign.
These facts clearly indicate that the headshake in LIS has a status different from that in, for instance, DGS and LSC. More specifically, the headshake in LIS is most probably not a featural affix and it is certainly not prosodic in nature. Rather, it seems likely that the negative sign is lexically specified for the headshake. From a typological point of view this means that LIS, in contrast to DGS and LSC, does not exhibit split negation. In LIS, negation is realized by a particle only.
Similar patterns have been described for other manual dominant sign languages such as, for instance, Hong Kong Sign Language (Tang 2006), Turkish Sign Language (Zeshan 2006b), and Jordanian Sign Language (Hendriks 2007). In these sign languages, too, the manual Neg sign is obligatory and it is impossible (or at least very uncommon) for the headshake to spread beyond the manual Neg sign. Clearly, spreading of the non-manual marker is not excluded in principle for manual dominant sign languages. Future research will have to determine whether it is in fact a general property of manual dominant sign languages that the non-manual marker is not prosodic but lexical – in contrast to the non-manual marker found in non-manual dominant sign languages. Such a correlation would imply an interesting typological division: non-manual dominant sign languages exhibit split negation while manual dominant sign languages use a simple negation (particle) strategy for negating a sentence.
So far, as far as the non-manual negation marker is concerned, I have only been concerned with a side-to-side headshake. In conclusion of this section, let me point out that the realization of the non-manual negation marker is also subject to cultural influences. As is well-known, in some regions, in particular, in the Eastern Mediterranean area (e.g., Greece and Turkey) and the Middle East (e.g., Jordan), a single backwards movement of the head is commonly used as a negating gesture by the hearing population. Not surprisingly, this gesture has found its way into the regional sign languages, where it is used as non-manual grammatical marker (usually alongside the negative headshake).
Obviously, the dynamic properties of the backwards head tilt (bht) are different from those of the headshake: while the headshake consists of repeated movements, the head tilt comprises only one single movement. Given the dynamic nature of prosodic features, it seems less likely for the head tilt to spread over a sequence of signs. Clearly, it cannot be synchronized with manual movements in the way the headshake can (see the discussion under example (9)). In fact, in Turkish Sign Language (Türk İşaret Dili: TİD), the head tilt, which accompanies the Neg sign, is not capable of spreading (31a) (Zeshan 2006b: 150). In other words: just as the LIS headshake, this non-manual marker appears not to be prosodic. In Greek Sign Language (GSL), too, a backward head tilt is commonly used in the context of negation. In (31b), as in (31a), the head tilt only extends over the sentence-final negative sign (Antzakas 2006: 265).
Still, GSL differs from TİD in at least two respects. First of all, in GSL, the backward head tilt is capable of spreading. In (31c), the head tilt extends over the whole sentence (Antzakas 2006: 265). The fact that the head tilt is capable of spreading (although this may be rare) suggests that it is a prosodic marker – just like the headshake in DGS. Secondly, in contrast to TİD, GSL is not a manual dominant sign language. As shown by Antzakas (2006), sentences can be negated by a headshake or a head tilt only. These patterns seem to confirm the typological division suggested above: GSL is a non-manual dominant sign language that has split negation while TİD is a manual dominant sign language that has simple negation.