So The Bird With The Crystal Plumage
(and most of Argento's films) are commonly referred to as Giallos
(Itallian thrillers that adhere to a fairly strict set of common "rules"). Most of the Italian horror films coming out in the 70s and 80s were made specifically with US distribution and consumption in mind. A lot of directors even went so far as to set films in American cities even though they were clearly filmed in Italy. These films are Italian language in nature but have most commonly been viewed with english dubs. Some of them never even retained their original language tracks for distribution and were shown in Italy with Italian subtitles because the dub track was the only audio available. The soundtracks to some of Argento's films are considered some of the best ever made.
If you're into hyper stylized thrillers and don't mind graphic violence you're in for quite a treat if you haven't seen any of Argento's work. The Bird With The Crystal Plumage is an excellent place to start for sure.