"Leto" (which I'm used to pronouncing/hearing pronounced as 'Leeto'),"Fremen" (which I'm used to pronouncing/hearing pronounced as 'Freeman'), and "Bene Gesserit" (which I'm used to pronouncing/hearing pronounced as 'benay jez-a-ret').
There are actors and actresses who pronounce "Leto" in a variety of ways. Some say LEE-to (the "o" is long, as in "toe" rather than "too"), and others say LAY-to. Just pick one and try to ignore the others. I don't think any of the productions ever had a proper continuity person who kept track of things like that. At this point I haven't reviewed Frank Herbert's own pronunciation guide to see if he has a definitive pronunciation he used.
"Fremen" is pronounced with a short "e" sound. Like in "red" or "bed" or "Fred." "FRE-men".
"Bene Gesserit". Okay, let's break this up a bit:
"Bene" has two syllables, emphasis on the first one. The first "e" is also short, like in "red", bed, or "Fred."
The second syllable's "e" is pronounced like "ay."
Put them together and you get "BE-nay."
(some online sources say it's "benny", which is WRONG).
Now for "Gesserit." The "G" is a soft "g", that sounds like a "j". The emphasis is on the first syllable, and the "e" is also short, as in "Fred, "bed," and "red." So the first syllable sounds like "Jess."
The other two syllables are evenly-emphasized, with the vowels pronounced as in RL. The "ser" part sounds like "sir".
Putting it all together, it sounds like "BE-nay JES-sir-it."
Bene Gesserit. "
Benay
Jessirit" (the accented syllables have been bolded).
My advice, if you ever watch any of Quinn's YouTube videos, is do NOT emulate his pronunciations. He's doing a lot of them wrong, he knows they're wrong, and doesn't give a shit how many people correct him. By the time he made the videos he had the Lynch movie, both miniseries, and a pronunciation guide by Frank Herbert himself to go by, not to mention people explaining latin pronunciation to him and he was rude to everyone.
Alia's name is pronounced "AH-lee-a". But of course if this movie ends right after the knife fight, the pronunciation of Alia's name won't be a problem until the next movie.