S. dissimilation of spirants; [θSθ] > [sSθ|θSs]

S. dissimilation of spirants; [θSθ] > [sSθ|θSs]

@@@ combine with final [θ] became [s] after another [θ], [ð].

In Sindarin words where there are repeated dental spirants, one of them tends to dissimilate away from the other. The clearest example is úthaes, which Tolkien said was the result of dissimilation in úthaeth (VT44/30). A deleted variant úsaeth indicates that dissimilation of the first spirant away from the second is also possible. Other potential examples include:

Hat tip to Elaran and Vyacheslav Stepanov for providing these last three examples.

Phonetic Rule Elements

[θSθ] > [sSθ]
[θSθ] > [θSs]

Phonetic Rule Examples

θaeθ > saeθ θSθ > sSθ thakta- > S. úsaeth ✧ VT44/30
θaeθ > θaes θSθ > θSs thakta- > S. úthaes ✧ VT44/30