Voiced uvular trill

The uvular trill is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ʀ, and the equivalent X-SAMPA symbol is R\. This consonant is one of the consonants collectively known as uvular R.

Features of this consonant:

Its manner of articulation is trill, which means it is produced by vibrations of the tongue against the place of articulation.
Its place of articulation is uvular which means it is articulated with the back of the tongue (the dorsum) against or near the uvula.
Its phonation type is voiced, which means the vocal cords are vibrating during the articulation.
It is an oral consonant, which means air is allowed to escape through the mouth.
It is a central consonant, which means it is produced by allowing the airstream to flow over the middle of the tongue, rather than the sides.
The airstream mechanism is pulmonic egressive, which means it is articulated by pushing air out of the lungs and through the vocal tract, rather than from the glottis or the mouth.

In English

English does not have uvular R, and most English speakers have difficulty pronouncing it.

French and German have a slight uvular R, e.g. F<rue> and G<Recht>. Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. ISBN 0-631-19815-6.