It's not super important to understand the whole story - but it shows you a bit more the real intention of a key detective from the Barcelona police department (funny enough: He probably wouldn't talk in Castilian with his peers, but in Catalan, if you know the "love" Barcelona and the whole region has for Spain and the Spanish language
).
So: There are two English subtitle tracks - the second one is especially for those Spanish (Castilian) only dialogues (when the police protagonist from Barcelona is talking to his colleagues) and these English subtitles are automatically chosen if you choose in the disc menu "English audio only" (with no subtitles). The "second" English subs (only for Spanish) can only be suppressed by remote.
Also: There are two German subtitle tracks - the same game: If you opt in the disc menu to see the movie dubbed completely in German with no subtitles, normally ppl talk in German, but these exact same Spanish dialogues are again subtitled in German (and spoken in Spanish only). So I guess maybe it's worth mentioning. If you ammend the entry, it should also be "German/Spanish Dolby Digital 5.1" (only figured this out now while double checking - I mostly don't watch German dubs if I understand the original language).
Turkish is not affected.