Indian prisoners of war of the First World War were held in Germany at the Halbmondlager, the half-moon camp, at Wünsdorf near Berlin, which was set up for Muslim and Indian prisoners as part of a propaganda effort to turn them against Britain.
German linguists made sound recordings of the prisoners speaking and singing in their own languages, for a phonetic archive. Those recordings survive in Berlin and include Punjabi speakers from villages in Punjab, recorded in 1916 and 1917, saying whatever they were asked to say.
They are the earliest recordings of ordinary Punjabi villagers' speech in existence and almost nobody in Punjab knows they exist.
Indian prisoners taken at Kut in 1916 were marched into Anatolia and a large proportion died.
In the Second World War, tens of thousands of Indian soldiers were taken at Singapore in 1942, and their treatment and their recruitment into the Indian National Army is a separate history.
A Punjabi farmer's voice from 1916, recorded in a German camp, is a primary source about Punjab and it is in a Berlin archive.
The camp had a mosque built for it in 1915, the first in Germany, put up as part of the same effort. It was wooden, it fell down in the 1930s, and the cemetery for the men who died there is still maintained.
The Lautarchiv at the Humboldt University holds the discs and cylinders with the record sheets that go with them: each speaker's name, his village, his district, his regiment, and what he was asked to say. The sheets are as much a document as the sound, because they name Punjabi villagers of 1916 one by one, which practically nothing else does.
The prisoners taken at Singapore in 1942 faced a different pressure and a large number joined the Indian National Army. The reckoning with that afterward was handled quietly and is still not written up honestly.