Complex sentence: Between the 1970s and 1990s Republican prisoners in Long Kesh prison spoke in Irish, and named the place "An Jailtacht", coming from the Irish word "Gaeltacht"-meaning Gaelic (or Irish) speaking region, and the English word "jail".
Split into simpler sentences: Between the 1970s and 1990s Republican prisoners in Long Kesh prison spoke in Irish. They nicknamed the place "An Jailtacht", a portmanteau combining the Irish "Gaeltacht" (Irish speaking region), and the English "jail".