A brief history of the author’s research on the Modern South Arabian languages (MSAL) in Oman and Yemen is given. Using Baṭḥari, the dangers of eliciting speech forms in isolation rather than recording continuous speech are illustrated. The value of comparing material from other languages of the study area, including Arabic dialects, is demonstrated. Lexis impoverishment is illustrated by discussing the many terms that were formerly used for ‘home’ in the MSAL. A discussion of possible social / cultural reasons for the decline of the most endangered MSAL follows, and the question of whether monolingualism was ever a reality for MSAL speakers is addressed. Examples of specialised vocabulary are given, Baṭḥari fishing terms, which illustrate the technical expertise necessary for the correct interpretation of texts, and how quickly this can be lost. A brief look at how MSAL speakers describe those who speak their languages imperfectly concludes the article.