Let’s be clear – this is not about accent.
Australian accents, broad or otherwise, are as valid as any other. And in fact, nasal resonance, as distinct from ‘nasality’, is a vital element in the blend of resonances that give our voices colour and carrying power.
Nasality like Hanson’s, occurs when sound leaves the body almost exclusively through the nose, limiting vocal range, depth and flexibility.
So what causes this irritating phenomenon?
For a range of reasons, the back of the tongue can tense up, meeting a lowered soft palate (the soft muscle above the back of the mouth), blocking the mouth and sending the sound through the nose.
Because of the enormous carrying power of nasality, it can be of great practical use, say, for calling across distances in remote areas. I think perhaps we tend to recoil from a nasal voice when it is used not for practical but for psychological reasons – when someone wants to be heard so badly that they subconsciously force people to listen. A nasal voice, especially at close quarters, is pretty unavoidable - and no-one likes to be beaten into submission, even vocally.
What’s the fix?
Restoring breath support is key, so that the muscles around the throat, tongue and mouth can release can free up the passage for sound, allowing other resonating chambers to join in with their full range of frequencies.
To check your sound, hold your nose and sigh out on a vocal “HAAAA”. If the sound is nasal, you’ll feel strong vibrations in your fingers. Sigh again from your belly and aim your voice through your mouth only. Speak something and notice what’s new.