When has English become dominant in Ireland?

superdavid   Fri Sep 21, 2007 5:17 pm GMT
I know there are two official languages in Ireland - Irish(Gaelige) and English.
However, hardly anyone speaks Irish as their first language and English is by far the predominant language spoken throughout the country.
It seems almost everyone in Ireland speaks only English now.

1. When has English become predominant language in Ireland?

2. Why Irish(Gaelige) language are starting to die out?
Is there any special reasons for that?