The paper discusses the main principles in designing and annotating speech corpora within the framework of the Saint Petersburg phonological school, and provides examples of using corpus data in phonetic research. One of the major principles that we follow is to analyse the speech material at all levels: from segmental to intonational, including speech disfluencies. During segmental phonetic annotation, we suggest listening to each speech sound in isolation (without knowing its context) and relying on spectrographic data. At the syllabic tier, it is crucial to reflect resyllabification. During prosodic annotation, we suggest to rely on listener’s perception of the intonation pattern first, then analyse the actual melodic curves. A speech corpus with multi-level annotation that follows these principles is a valuable source of phonetic data — as segmental and prosodic factors are in constant interaction with each other, and one cannot analyse units of one annotation tier without reference to other tiers.