In the German VERBMOBIL project, segmentation and labelling of recorded speech data is a fundamental part of the research. The following procedures are adopted [Kohler et al. (1995)]. The phonemic labels are based on the SAMPA symbols for German, augmented by extra labels for phonetic segments such as plosive release, aspiration after a plosive, creak, and nasalisation of a vowel as a reflex of a deleted nasal . Hence the labelling is partially carried out at the narrow phonetic level, being basically phonemic.
During the labelling process, a label will be aligned with the start of the portion of speech that is considered to represent its chief acoustic correlates. Labels are discrete and non-overlapping, except in the following cases:
Inter-labeller consistency is maintained in three ways, as follows:
The checking of segmented and labelled speech files is carried out partly by a program developed at IPDS Kiel that detects invalid sequences of symbols, and partly by experienced labellers checking the work of less experienced transcribers [Kohler et al. (1995)]. All segmenting and labelling is carried out manually. The initial citation-phonemic transcription is generated at IPDS Kiel with the help of the grapheme-to-phoneme converter of the Rulsys/Infovox TTS system for German [Kohler et al. (1995)], subsequently checked manually for mistakes. A system of prosodic labelling has also been developed: PROLAB [Kohler et al. (1995)].