Christian Brothers, Graiméar na Gaedhilge (1906)
“ Now, if we wish to get the sound of b aspirated (or ḃ) , we must breathe the whole time whilst trying to form the sound of b; i.e. we must not close the lips entirely, and the resulting sound is like the English consonant v. Hence we say that the sound of ḃ (in some positions) is v. The Irish letter c corresponds very much to the English k, and the breathed sound of k corresponds to the sound of ċ (when broad) . To sound the English k, we press the centre of the tongue against the palate, and cut off the breath completely for an instant. ”
