Take a look at the OS X system preferences under Keyboard there is a button on the lower-right named "Modifier keys" where you can define which actions should be taken by the modifier keys (caps-lock, ctrl, cmd,...). There's an option to disable the cmd key. And with the free software... - MacBook Core 2 Duo
As shown in this image, to insert the word “බෞද්ධයන්“ just press “2”. It’s that much easy. The good news is this option is available for Office and Unicode both typing modes. Also you can change the maximum number of words to be suggested and even you can disable this auto word suggestion option via Settings.