He asked eighteen phoneticians to listen to a recording of ten words spoken by a native speaker of Gaelic and to place the vowels on a cardinal vowel quadrilateral. He then studied the degree of agreement or disagreement among the phoneticians. Ladefoged himself drew attention to the fact that the phoneticians who were trained in the British tradition established by Daniel Jones were closer to each other in their judgments than those who had not had this training.