I recently upgraded my Nokia Lumia 800 to a Lumia 520, so I am now running Windows Phone 8. It has been a good experience so far, a nice step up from Windows Phone 7. However, one thing that has been bugging me is that it refuses to capitalise my i's. So I type i followed by a space and it stays as a little i. Hardly a massive problem, just a little irritation. I tried "training" it by correcting i to I a multitude of times but had no luck. Eventually, after digging around on the internet for a while, I found a post on some forums where a user mentioned it being a bug with the En/GB keyboard. So I switched to En/US and lo and behold, my i's are now being capitalised. Hooray. To change your keyboard to the American version go to:

Settings -> Keyboard -> Add Keyboards -> Select English (United States)

It will download and install the new keyboard, you can then remove your En/GB keyboard to get the wide spacebar back if you so wish. So if you don't mind capitalise becoming capitalize, all is well. I have contacted Microsoft for confirmation of whether it is a bug and if a fix for it is on the roadmap but have received no reply as of writing this post