Typing away only to have a key stop registering, or gliding your finger across the trackpad and watching the cursor do something completely different to what you intended, is one of the more maddening ways a Mac can let you down. These faults rarely feel urgent at first, a missed letter here, a slightly stiff click there, but over time they chip away at your patience until even basic tasks like...
Deutsch 
English
Arabic
French
Spanish
Portuguese
Turkish
Dutch
Italiano
Russian
Romaian
Portuguese (Brazil)
Greek