Crosslinguistic Connections for the pied-piper in old Japanese
Evidence for the pied-piper feature is not limited to the diachronic change in Old Japanese. It is also found in optional wh-movement languages. Clements (1984) observes that a preposed wh-phrase is accompanied by a focus particle in Kikuyu. Compare the examples in (1).
(1)

The focus particle ne´ is attached to the fronted wh-phrase o to form no.o in (1b). The same focus particle is used for the fronted non-wh focus, too, as in (2).
(2)

Sabel (2000) takes this focus particle to be the realization of the focus feature as in the analysis of Old Japanese in Watanabe 2002, though Sabel assumes that this feature is interpretable. Given the perspective taken here, however, this Kikuyu particle is also a good candidate for the realization of the pied-piper feature.
Bergvall (1983) obseves that wh-in-situ in Kikuyu is sensitive to the Complex NP Constraint, as illustrated in (3) (tone omitted).
(3)

As suggested in Watanabe 2004b, the Complex NP Constraint effect can be reduced to the locality of Agree, once it is shown that the D head of the complex NP contains a feature that is probed by the interrogative C. Recall also the earlier discussion of locality in HIRCs and the indeterminate-particle association. I speculate that the feature in question is related to quantification, though exploring the idea goes well beyond the scope of this chapter. The important point here is that the Kikuyu wh-in-situ makes use of agreement, so we are led to assume that it contains an uninterpretable focus feature. The focus particle itself, then, should be analyzed as the realization of the pied-piper feature.
Thus, if a particle is attached to the preposed wh-phrase, it is a candidate for realizing the pied-piper feature. A particle attached to wh-in-situ, on the other hand, cannot be a realization of the pied-piper feature. Suga hara (1996) and Miyara (2003) discuss the particle that accompanies wh in-situ in Okinawan, illustrated in (4).
(4)

Sugahara and Miyara share the view that this particle hosts the wh feature, but Miyara characterizes the difference between (5a) and (5b) by saying that (5a) is emphatic, indicated by the addition of ‘on earth’ in the translation.
(5)

It then seems reasonable to treat the particle ga on a par with the particle ka in Old Japanese after the loss of wh-movement, namely, as an anti-D linking marker.
According to Kishimoto (1992), Sinhala has a particle similar to the one in Okinawan. Even though Kishimoto does not comment on its se mantic effect, it is likely that it is also an anti-D-linking marker.