The paper discusses several linguistic peculiarities of three endangered Caucasian languages of Georgia that are currently being documented within the DoBeS “ECLinG” project, viz. Svan, Tsova-Tush (Batsbi), and Udi. The main focus lies on questions of the phonology (vowel systems, pharyngeal and laryngeal subsystems) and the morphosyntax (verbal agreement, ergativity) of these languages. The second part of the paper is devoted to the question whether the audiovisual material collected in the course of the project admits of establishing linguistic parameters of language endangerment with respect to the languages in question.