A Welsh speech database intended for use in phonetic research requires careful annotation at several linguistic levels. The initial stage is that of labelling at the acoustic phonetic level, where the closure, burst and aspiration phases of a stop consonant are all separately labelled. The next is the phonemic stage, which can be derived from the former in most cases. Next is the syllabic stage, where each syllable is labelled in terms of its word status and in terms of lexical stress. The final stage is the lexical stage, where each word is labelled according to its word class. A statistical package can then be run over this data to yield information on the acoustic characteristics of Welsh speech sounds, and also about the nature of lexical stress in Welsh. In addition, it is hoped to derive rules for intonation patterns for use in an existing Welsh text-to-speech synthesiser.