Problem with alternative character input

Hello to all,

I have a problem with the alternative characters input after Mavericks upgrade.

The function i talk about is this: http://support.apple.com/kb/HT4896

When i press and hold the 'e' key, for example, in order to submit the accented 'E', the program I'm using is stuck (whether it's Chrome or Word), and only after five minutes it restarts to work

In any case the whole system is so slow that when you save a Word document, the system treats it as a Cinema 4D rendering operation.

The language of my keyboard is italian.

I called Apple for service.

They were just able to suggest me how to do the accented 'E' in another way.