In speech studies, data base access has been significantly improved through the use of label files which relate portions of the speech waveform with a phonetic (or phonemic) transcription as well as other linguistic and nonlinguistic information. In this way the acoustic and linguistic “realities” of speech can be associated and checked against each other since they were derived independently. Because of the lack of a simple correspondence between the acoustic structure of a portion of the speech waveform and the linguistic label assigned, additional principles must be invoked to make labels useful. As an example of the labeling process and the accompanying problems, a sound identification study is described in which 675 vowel nuclei were labeled using the transcription derived from a sophisticated multitranscriber system. Despite precautions taken to insure correct labeling, many of the vowels are judged in a pattern recognition experiment to be more similar to neighboring vowels in the vowel space or to schwa than the vowel they were labeled as. These supposedly misidentified vowels were found to have acoustic structures very different from the ideal for their label, at least partially due to the loss of coarticulatory and vowel reduction information when assigning transcription symbols. Directions for resolving these problems and for increasing the utility of labeled speech events in acoustic and linguistic processing are discussed. [Work supported by AFOSR Contract No. 44620-74-C-0034.]