er, why is that remotely daft? I'm not having anything both ways.

Similar. Not 'absolutely identical'. Not 'completely and utterly indistinguishable' .

Obviously NIck was male and his sister and mother are/were female. So there are gonna be some rather obvious differences.

But in terms of accent, cadence, timbre, the voices of Nick Drake's sister and mother are similar to the voice of Nick Drake.

And the voice of Nick Drake does not change much over the course of his albums.

Funnily enough, he sings on Pink Moon not dissimilarly to how he sings on his teenage home recordings.

As I mentioned above, he does do a funny enunciation thing on his "Ks" (both Donovan and Mark E Smith (!) do something similar) All singing is affected or stylized in some way, however tiny. But I'd say Nick Drake has one of the least affected voices, in terms of accent, in terms of delivery, of any singers ever. There are hundreds of more affected voices: think of any number of Drake's blues-singing British peers.

You can hear his speaking voice on the 'Family Tree' album. It's like his singing voice: the same gentle, rather breathy timbre, only deeper.

(Most people, I find, tend to sing in a slightly higher register than they speak. I certainly do. Aside from the obvious - you don't consciously pitch your speech - it's probably to do with the fact that you tend to sing louder than you speak)