Why did they film this in English?

What in the hell are you guys talking about? This movie was filmed in German, obviously you saw a dubbed version.

« Because an English-language film has a bigger market.»

Not a very good argument and less valid every year : a Chinese version may have just as large a market and in any case often movies are post-sync'ed in studio because of heavy accents, poor recording quality in the open, bad singing, etc.

So an English movie may be post-sync'ed in English...

Some foreign-language dubbing is so good that you can hardly notice it : Spartacus from English into French is bluffing, the Barber of Siberia from Russian into French is very good, some Chinese and Italian movies are also very well dubbed into French. Not always the case of course, unfortunately. For very good dubbing, the dubbed version may actually be better than the original. The voices selected are only chosen for their sound/sonority/diction, not their looks. (Some pretty American actresses have annoying voices or accents.)

Now, what is true is that dubbing into English is usually poor (by lack of practice, design?) so it may be better to film in English so that the poor Americans aren't left with a substandard product.

But the US market will count for less and less in the future. Just heard that the just-released Le Dernier Loup/Wolf Totem had one million spectators per day in China in the first days of its release for instance. Remember, the USA = 5 % of the world population. As the rest of the world has more disposable income, the importance of US market will decrease relative to other ones.

Does the English audio even exist anymore?

This film was recorded in a variety of languages. The natives spoke in whatever language they spoke, and in some scenes, such as when the interpreter is speaking to the man who listens to the Bible and then throws it down, the natives spoke in different languages back and forth and had no idea what each other were saying. Most of the natives knew basic Spanish and communicated with Herzog that way. Some actors did indeed speak in English, while others, such as the lead Kinski, spoke in German. The movie was later dubbed not for convenience but to reconcile all the languages and also to make up for terrible sound quality. Kinski demanded $1 million to come in and dub his part. Since the movie had a rather tiny budget (around 300k or so total I think), they brought someone else in to dub the Aguirre character. It sounds so great that Kinski himself didn't even realize it wasn't him! If Kinski would have spoken in English in the original filming, he would of course notice the change to German in the dub.

My source: Werner Herzog. He came to speak about Aguirre particularly at my school two weeks ago (University of Colorado). The movie crew had no electricity so on top of limiting audio equipment, there is no artificial lighting in the entire movie. It truly is an incredible work of art.

PS: My favorite little tidbit I'll share: the scene where they wake up and discover the river has flooded was unplanned. The river actually flooded and Herzog had to rewrite the entire script to incorporate the flood. Just shows you how involved with reality this movie was!

It doesn't matter what language they were using, it was all dubbed. had to be because of where they were filming. The background noise, water, birds, wind would have drowned them out.

And I have to say, in the English language version I just watched -- that was NOT Mr. Kinski's voice. I've heard him speak English before and THAT was not him.