The development of speech sounds always has its own regularity, but there are also some exceptions.

语音演变有很强的规律性，但也有例外。

youdao

"We think the very first processes of language development are actually starting in the womb because they are overhearing their mother's speech."

VOA: standard.2010.05.05

With the likes of Google, Nuance and Vlingo now offering mobile speech-recognition services for phones, and the development of speech-driven systems for use in vehicles, Parakeet may be flying into a growing market.

ECONOMIST: Monitor

In humans the vocal tract acts as a filter on the sound from the source, and the "source-filter theory" held that the separate, fine control of the vocal tract to be the product of a long evolution in the development of the subtleties of speech.

BBC: Helium-huffing gibbons 'sing with soprano technique'

The technology reflects more than one million hours of research and development in speech technologies that has led to more than 600 U.S. patents and patent applications.

ENGADGET: QNX builds in-car speech framework with AT&T's Watson, knows our true intentions