Double tonguing can be one of the most essential techniques to know on the flute, it can be one of the most impressive techniques, but it is also one of the most daunting things to learn on the flute. I'm here to tell you that it is actually quite simple to double tongue on the flute.
First, if you don't know how to single tongue (or regular tongue) on the flute, then you should read my article on single tonguing first.
While the premise of single tonguing is saying the syllable: "too"
The premise of double tonguing is saying: "too koo"
Practicing this with slower articulations could halep build up evenness with your double tonguing as it can sound very amateurish if you are not even with each of the syllables.