Google today introduced Voice Search support for Zulu and
Afrikaans, as well as South African-accented English.
Google defines underrepresented languages as those which, while
spoken by millions, have little presence in electronic and
physical media, e.g., webpages, newspapers and magazines.
Underrepresented languages have also often received little
attention from the speech research community. Their phonetics,
grammar, acoustics, etc., haven?t been extensively studied,
making the development of ASR (automatic speech recognition)
voice search systems challenging.
Google believes that the speech research community needs to
start working on many of these underrepresented languages to
advance progress and build speech recognition, translation and
other Natural Language Processing (NLP) technologies. The
development of NLP technologies in these languages is critical
for enabling information access for everybody. Indeed, these
technologies have the potential to break language barriers.
Google has collaborated with the Multilingual Speech
Technology group at South Africa?s North-West University led by
Prof. Ettiene Barnard (also of the Meraka Research Institute),
an authority in speech technology for South African languages.
The company's development effort was spearheaded by Charl van
Heerden, a South African intern and a student of Prof. Barnard.
With the help of Prof. Barnard?s team, Google collected
acoustic data in the three languages, developed lexicons and
grammars, and Charl and others used those to develop the three
Voice Search systems. A team of language specialists traveled
to several cities collecting audio samples from hundreds of
speakers in multiple acoustic conditions such as street noise,
background speech, etc. Speakers were asked to read typical
search queries into an Android app specifically designed for
audio data collection.
For Zulu, Google faced the additional challenge of few text
sources on the web. Google often analyzes the search queries
from local versions of Google to build its lexicons and
language models. However, for Zulu there weren?t enough queries
to build a useful language model. Furthermore, since it has few
online data sources, native speakers have learned to use a mix
of Zulu and English when searching for information on the web.
So for our Zulu Voice Search product, Google had to build a
truly hybrid recognizer, allowing free mixture of both
languages. Its phonetic inventory covers both English and Zulu
and its grammars allow natural switching from Zulu to English,
emulating speaker behavior.
This is Google's first release of Voice Search in a native