Irish Gaelic: Typing those odd characters
English doesn't have acute symbols or accent marks in normal spelling. Except for some obviously foreign loan words, we don't have dots or tails or lines floating around in written English (well, with the possible exception of teenage girls dotting their i's with little hearts and such). We tend to denote changes in pronunciation by using letter combinations or other spelling peculiarities -- or we don't differentiate at all and you have to learn the rules of how things are pronounced in different situations.
Not the best scheme, if you ask me.
Irish, on the other hand, has two written versions of each vowel, a long and short version. The long version is denoted by an accent mark over the vowel: á, é, í, ó, ú. When spelling out loud, the accent mark is also noted -- as in á, a-fada. For example, Caít is: c-a-i fada- t.
Many other sites can explain what these sound like and the rules about using them (see here, for example), but I'll explain how to write them in a normal text editor or word processor without having to install separate keyboard mappings.
Typing these special characters can be done by referencing their ASCII equivalents, which can then be typed by using the ALT key and the numeric keypad.
For example, á is type by pressing the ALT-key + 0225. Make sure your numlock is on.
It's actually quite easy to manage once you've done it a few times.
This works fine if you need to type an odd Irish word here and there. If you're going to type alot of Irish, I'd definitely go the route of installing the new keyboard mapping, to save some time. It's possible to swap keyboards on the fly in most versions of Windows.
Check here for instructions on how to install and use alternate keyboards. If you're using a Macintosh, try here.