When we found ourselves deaf to a sound distinction, I at once concluded the difference must be tone, because all the other possibilities involved sound distinctions I know I'm not "deaf" to, and I'd already heard that a related language was tonal.
We'd been doing sound sorting with first-syllable vowels, but that was pretty easy. In Phase 1, we have small drawings for each earlier vocabulary item, and use them for different purposes, including sound sorting. If you've forgotten what sound sorting is, in the case of initial vowels, it means listening to the words again that go with the drawings, and as you do, arranging the drawings in columns of words that all begin with the same vowel. It was definitely helping us to hear the vowels better, but there were no distinctions we could not here.
When we discovered there were tones, and we were "deaf" to them, we took the picture of the broom and the one of the window as the headers for two columns, and then we stared trying to put other pictures into one column or the other based on whether they had the tone (pattern) of "broom" or "window" (and "broom" and "window" were also taken as the "names" of the two tones (patterns) so that the nurture could tell us for new words, which tone it was).
So we're sound-sorting words by tones.So far, not so good, but we believe it will get better. One problem is, of the two tones (patterns) one is not very common, so we have hardly any drawings in that column and a ten-foot-long vertical strip of little drawings in the other column. To make matters worse, we read now that there are three tones (patterns) in these languages. We thought we had an example of the third, but it turned out not to be so. Still looking.
We'll let you know if and when we overcome our "deafness"