I have not forgotten the one time I heard Joan Sutherland sing live.

It was a concert performance of Anna Bolena at Avery Fisher Hall in New York. I sat way up in the back in the uppermost row of seats. Sutherland's voice hovered around my head, creating the impression that she was standing right before me. Perhaps the most amazing acoustical phenomenon I'd heard in my life, it was clear why the Italians named her La Stupenda. However, though surrounded by an astonishing tone, I hardly understood a word she sang. How could someone so preternaturally gifted be so deficient regarding diction? Was she lazy? Hardly. Even a cursory glance at her performance schedule revealed that she was a workhorse. Was it a technical matter? Was she just not putting her tongue in the right place? This doesn't seem plausible, considering Sutherland's intelligence and work ethic. So, what accounts for the matter? After studying Sutherland's singing and face, I believe it to be a matter of mixed dominance.

Since the right ear actively processes higher frequencies faster than the left, a knowledge of acoustics gives us the answer. The simple fact is that sibilants—sounds like S, Z, SH, ST, TH, and so forth—are high-frequency sounds. When the left ear leads, these sounds are dulled. The voice may still have a great presence, as Sutherland's singing certainly did, but diction is affected.

There are other consequences besides indistinct diction.

A left "leading" ear can indicate learning and language problems and problems with memory. With that in mind, consider the following from Sutherland's biographical information.

Even as Sutherland entered her sixties, she was able to take on new roles because of her dedicaton and skill, even though learning new roles was hard for her because of a relatively poor memory. Encyclopedia of World Biography, 2004.

One way to understand the matter is in terms of light. Higher frequencies are analogous to greater light. When there is more light in a room, everything makes a clearer impression. As such, the objects in the room come into focus in a way they do not when the room is darkened. Do you see where I am going here? It is the same with memory: when auditory information is processed via the right ear, it makes a clearer impression. It is better remembered. When the left ear leads, memory can be affected

If you watch Sutherland closely in a succession of video clips at Youtube—observing the direction of her mouth on every vowel, you will see that it points to the right when she is singing /i/. (Don't forget: her right—visually speaking—is on your left!) This makes sense since /i/ has the most significant "ring" concentration, i.e., higher frequencies. Speaking empirically, my observation is that /i/ and /e/ naturally tend towards the right, while /o/ and /u/ tend towards the left. Since the Old School was emphatic regarding the student mastering /a/, one might conclude that /a/ is a "middle" vowel—needing the qualities of both /i/ and /u/.

(Curiously, Margaret Harshaw taught that a "perfect vowel" combined all three—/a/, /i/ and /u/. She also held Sutherland as an excellent example of bel canto tonal production, keeping a picture of her mouth on her studio piano.)

It's interesting to contemplate what might have transpired had Sutherland undergone a course of Listening Training, as this awakens the right ear from its slumber.

I'm betting I would have better understood her words.

Note October 8th, 2019: Since the original video clips accompanying this post are no longer available, readers are encouraged to conduct their own research on YouTube, watching Sutherland’s mouth and face during spoken interviews and singing.