The writer of the identical letters threatened Mr. Bloomberg, one of the nation's most vocal advocates for gun control, and made references to the debate on gun laws.

WSJ: Letters to Mayor Bloomberg Tested Positive for Ricin

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'

Even if a grand coalition holds together, it might be pushed by a vocal opposition into populist policies such as tighter immigration control.

ECONOMIST: Austria's election

As the team report in the American Journal of Physical Anthropology, the apes were able to control the natural frequencies of their "vocal tracts".

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

And some Republican leaders who are now decrying the sequester were very vocal in their support of it as part of this package, the Budget Control Act, last year.

WHITEHOUSE: Press Briefing