The Lezgic languages are relevant to the glottalic theory of Indo-European, because several have undergone the voicing of ejectives that have been postulated but widely derided as improbable in that family. The correspondences have not been well worked out (Rutul is inconsistent in the examples), but a few examples are:
Non-Lezgic: Avar tstsʼar; Lezgic: Rutul dur, Tsakhur do 'name'