This is one of the best movies I ever watched but there is something that's been bothering for quite a while.
How did Antonio Banderas' character know the words for that Viking prayer? To avoid misunderstandings, I mean this scene: https://www.youtube.com/watch?v=tL1acYvpR_E. We can see him reciting the prayer with the rest of them, but his character was Muslim. So how did he know what to say? That's not something you can make up on the spot.
Early on in the movie, during the Viking funeral that Banderas and Sharif's characters come across, we see Sharif translating the Viking prayer for Banderas as it's being said. Sharif says it very flat and matter of factly, but it's the same. So at the end, when Ahmed (Banderas) hears it, he remembers it from before and is able to recite it.
He also learned to speak the language early on in their journey and had been hanging out with them the whole time, so it's possible he inquired about it or had it taught to him at some point..
It's one of my favorite scenes.... A prayer and action that seem so foreign and 'out there' in the beginning. He sneered at it. By the end of the film, he recites it with them- it has meaning to him, it holds weight with his prayers. It was with honor, that he recited the prayer that they held dear- he became as close to a Norseman as he could in that moment.
he was listening and learning their language while on the journey. He was also listening some prayers in early scenes (the funeral). His ability to be able to learned foreign language have some backing, his background as a poet would have a base knowledge of language and structures those give some merit to it.