Some people spend a lot of time at their keyboards. I started reading this thread to find good mnemonic and found several but the rest of the discussion has been fascinating. I forget who made the point about beginners and simplified stories but it reminded me of when I was teaching myself to play the concertina. This was relatively late in life, well after I had bought and listened intently to Glen Gould's collection of the Well Tempered Klavier and was thus aware of Bach's intent on the piano, but I had to learn by ear, as I didn't (and still don't) read music beyond the finger-counting level.

It was a 20 key anglo in C/G, with no accidentals. Most of the tunes in sessions seemed to be in ... I was about to write "D, G and A major or their relative minors." As several of the instruments were button accordions (A,D,G), concertinas (English) or concert flutes (all 'modern' and thus tuned in mean temperament) I suppose I should be more precise but you get my drift. Although I had a good sense of relative pitch (being a member of a rather accomplished group singing a cappella harmonies) I could follow the tunes OK but couldn't pick which key they used. Not wishing to cause trouble I attempted only the tunes I could play on the G row. This meant I kept a sharp eye on which row my ADG accordion mate was using whenever the tune changed.

I remember one session I had to lean past a very senior and accomplished fiddler to see whether my mate's fingers were on the inside (G) row or the middle (D) row. I was in luck! He was playing the inside row, so I could join in.
"Ah, G!" I muttered as I sat back.
"A minor!" the senior and accomplished fiddle player sternly corrected me.

I kept on trying to play the tune but I was now confused. I had been exposed to just enough music theory to know that scales in minor keys used one set of notes when ascending and a different set when descending, Yet, a diatonic melodeon in C with only one row of buttons could play tunes in minor keys (mostly described as "D minor" but some described as "A minor") as well as tunes in "C major". What was going on? An orchestral violinist who also happened to be a folkie fiddler told me about temperament, scales, modes and keys. I was away at last.

In Melbourne at the time we had Chris Wendt, who played highland pipes, fiddle and anglo concertina. His favourite concertina was the same as mine, a 20 key Lachenal, but he had retuned it so that it played in just temperament with D as the tonic and the notes in modern pitch, ie A=440. It was the sweetest concertina I've ever heard but he could only ever play it solo. If anyone else tried to accompany him (even fiddlers) it usually sounded off because either their instrument was mean tempered (but otherwise pleasant) or their ears were not attuned justly.

Since then I've had many occasions to get inside my concertina and, on several of these, was accompanied by Geoff Wooff who played English concertina (and Northumbrian pipes)and repaired lots of different concers; these days he makes and plays uillean pipes. Whoever it was in the thread above who made the comment about the difference between electronic tuners' versions of pitch and a good ear's version of 'correct pitch', they certainly spoke the truth.

But that reminds me of a paper I heard of, 30 years ago now, that made a point I suspect some of you may find interesting, even relevant. Someone went and did the Percy Grainger thing and recorded solo singers, from around the boondocks of England, singing unaccompanied. Unlike Percy (who transcribed the precise notation of every minute variation in pitch and timing, setting the cat amongst the academic pigeons) the person then fed the recorded singing through a frequency analyser.

According to my (now ancient) memory, they found the recordings split into two groups. Those singers who had grown up exposed to pop music or classical music had overtones of thirds and fifths in their (solo) voices, while those who'd grown up without exposure to such music had overtones of fourths and sevenths. This seems interesting, in the context of this thread. Does anyone have any memory of such a finding?