If you're an American using US American Siri on American soil, I'm sure Siri is an absolute dream - but for the majority of the world's population, "Siri sucks" isn't so much a clichéd argument but a daily reality. As for myself, I'm Swedish but I speak US English with no discernible accent. Here are my options:
iOS+MacOS: Swedish or English. If I set it to Swedish, I can get Siri to do some basic things like triggering shortcuts or taking calendar appointments, provided I remember that Siri doesn't understand 24hr time properly, e.g. if I say that the event is "from 16 to 19" (4 PM-7 PM) it'll be written to the calendar as 4:19 PM to 5:19 PM. If I tell it to play music, which typically involves English song titles and artist/band names, I have to do it in a really thick Swedish accent (aka 'Swenglish') because it's using an algorithm that Apple created while training Apple TV to understand Swedes saying stuff like "Taylor Swift" or "The Avengers". Pronouncing the names/titles with a US English accent will confuse the hell out of 'Swenglish' Siri - the better your English, the less she'll understand. If I set it to US English, I can do everything you do as far as dealing with Apple Music / TV+ etc, but it breaks everything else; Every Swedish push notification or text message I receive will be read to me like they were written in English (which is great for comedic effect but 99.8% unintelligible), and obviously Siri won't understand a word I say with regards to Swedish map locations, local establishments etc.
tvOS: Swedish/'Swenglish' only. The system refuses to allow me to select English Siri (or any other language except Swedish) for no apparent reason. I posted (polite) questions about this absurd restriction on Apple's support forum and both posts were deleted in under 5 minutes like I exposed the world's most sensitive military secret or something.
Google Assistant: I can set it to Swedish, English or both simultaneously. If I set it to Swedish only I can still address it in English or Swedish and switch mid-sentence, and the assistant will still understand me and respond in Swedish. If I enable both languages, the assistant will respond in whichever language I addressed it. The bilingual option is supposedly in beta, but it never failed me so far. That's why I as an avid Apple devotee have a house full of Google gadgetry. Well, that plus the fact that Apple adamantly refuses to sell HomePod in my country nearly 3 years after its original launch.
In case you didn't know or care, this is a long-standing issue with Apple - they love taking your money no matter where you're from, but they're as US-centric as Trump when it comes to their software and services, and only at gunpoint will they make anything work properly for people outside the native English speaking realm.
