"The Foggy Dew" is an Irish patriotic folk song dating to around the time of the Easter Rising (1916) in Ireland. The song mostly tells of how during World War One, Irishmen were being drafted by the British Empire to fight for the British, however many of these soldiers drafted were middle-class Irish citizens, who would end up dying on the shores of modern-day Turkey. The song expresses this distress, saying how these brave men would have been better used defending Ireland in the War of Independence, rather than dying for the British Empire, the colonizing power that had oppressed them for nearly 800 years.
Suvla and Sud-El-Bar are cities in modern-day Turkey, and where battles between the British and the Turkish Ottomans took place. Many of the infantrymen who made up the main British forces in these two battles were directly from Ireland, and many of them died during these battles.
Audio in question is "The Foggy Dew - The Young Wolfe Tones"