Not long at all
Before the iPhone, I'd only sent one or two texts from my 10-pad Razr and I have big hands.
With the iPhone, I started with 1 finger typing and being very careful. Sure I'd hit the wrong key sometimes, but the autocorrection fixed 98% of them.
Once I got more proficient and began to trust the autocorrect (1-2 hours), 1 finger was slowing me down. I switched to two-thumb typing and quickly got up to speed on that. I don't even thing about the keyboard now, I just type!
Before the iPhone, I'd only sent one or two texts from my 10-pad Razr and I have big hands.
With the iPhone, I started with 1 finger typing and being very careful. Sure I'd hit the wrong key sometimes, but the autocorrection fixed 98% of them.
Once I got more proficient and began to trust the autocorrect (1-2 hours), 1 finger was slowing me down. I switched to two-thumb typing and quickly got up to speed on that. I don't even thing about the keyboard now, I just type!