Hi Hernandez! It's either "Today we are going to talk about the pronunciation of 30 brands that exist in Brazil, THAT are pronounced differently in English” OR "Today we are going to talk about the pronunciation of 30 brands that exist in Brazil, BUT THEY are pronounced differently in English”. I hope it helps!

"but that" is perfect!

"but that" is correct. English Grammar in Use with answers, 5th edition, by Raymond Murphy. Unit 92 Relative clauses 1: clauses with who/that/which, p. 184. In relative clauses we use WHO/THAT/WHICH, not HE/SHE/THEY/IT. Compare: I can't find the keys. THEY were on the table. Where are the keys THAT were on the table? (NOT the keys they were)

I don’t get it. There’s a relative clause at the beginning of the sentence, which is “Brands THAT exist...” The “That” is referring back to “brands”. Why can’t I say then “that exist in Brazil but THAT are pronounced...” ..................................... In an English-teaching website post, written by a native speaker, I found this sentence “What are homophones? Words THAT are spelled differently and have different meanings BUT THAT are pronounced exactly the same.” He doesn’t say “but THEY are pronounced exactly the same”. This sentence has the very same structure as mine. Why can’t I use “but THAT are” in my original sentence then? .......................................... Besides, in another website, I found yet another example that has the same structure as mine. The post read: “Here are some examples of words THAT sound like speech BUT THAT are really gibberish nonsense with no meaning”. The author didn’t say “but THEY are”. Why then should I use “but they” and not “but that” in my original sentence? What’s the difference between my original sentence and these two other sentences I showed you? Thank you very much!!!!