|PhoneBook is a phonetically-rich, isolated-word, telephone-speech database,
created because of (1) the lack
of available large-vocabulary isolated-word data, (2) anticipated continued
importance of isolated-word and
keyword-spotting technology to speech-recognition-based applications over the
telephone and (3) findings
that continuous-speech training data is inferior to isolated-word training for
The goal of PhoneBook is to serve as a large database of American English word
all phonemes in as many segmental/stress contexts as are likely to produce
coarticulatory variations, while
also spanning a variety of talkers and telephone transmission characteristics.
We anticipate that it will be useful in ways analogous to TIMIT/NTIMIT.
The core section of PhoneBook consists of a total of 93,667 isolated-word
utterances, totalling 23 hours of
speech. This breaks down to 7,979 distinct words, each said by an average of
11.7 talkers, with 1,358 talkers
each saying up to 75 words. All data were collected in 8-bit mu-law digital
form directly from a T1
telephone line. Talkers were adult native speakers of American English chosen
to be demographically representative of the U.S.
Given the large set of talkers being recruited for PhoneBook database, it made
sense to exploit the opportunity to collect additional utterances. We have
chosen spontaneous numerical utterances, because of
widespread interest in them and the need for very large numbers of talkers for
research into spontaneous-speech effects. We restricted to just three spontaneous digit sequences and
one money amount, as the lists
for the core of PhoneBook have been designed to approach the limit of
reasonable duration for a caller's
session. As a result, PhoneBook contains a total of 5,105 spontaneous utterances.