why do irish people not speak ''irish'' (22)

Irish was the predominant language of the Irish people for most of their recorded history, and they brought their Gaelic speech with them to other countries, notably Scotland and the Isle of Man where it gave rise to Scottish Gaelic and Manx.

It has the oldest vernacular literature in Western Europe. It began to decline under British rule after the seventeenth century. The nineteenth century saw a dramatic decrease in the number of speakers partly due to the Great Famine of 1845–1852 (where Ireland lost half its population either to emigration or death) and partly due to strict government language policies enforced by the British. Irish-speaking areas were especially hard hit. By the end of British rule, the language was spoken by less than 15% of the national population. Since then, Irish speakers have been in the minority except in areas collectively known as Gaeltacht. Ongoing efforts have been made to preserve, promote and revive the language.