[disc]

I switched to Dvorak 11+ years when I was in college and had a lot of time to kill. I think your spoken language fluency analogy is pretty accurate; I imagine I'll always retain a bit of my 'native' qwerty muscle-memory, but the more I practice it, the easier it is to make the mental 'switch' between languages.

That said, if I had to do it all over again, I wouldn't switch to Dvorak. The efficiency gained on my keyboard layout does not offset the efficiency lost on shared computers.

[nknighthb]

I definitely wouldn't suggest anyone switch for performance reasons. I switched because of pain. It helped that a lot. Made virtually no long-term difference in typing speed.

(Then again, my typing speed has been 90+ wpm since I was about 9, so I'm an outlier in various ways.)