Definition of double tonguing in US English:

double tonguing

noun

Music
  • The use of two alternating movements of the tongue (usually as in sounding t and k) in playing rapid passages on a wind instrument.

    • ‘The reason for the development and employment of double tonguing is quite simple: it enables the player to articulate faster than is possible with the single tongue.’
    • ‘This is a great starting tempo for double tonguing.’