If I remember correctly he was indeed latino. His mother was a rebel in Santa Prisca and he was born in a prison on that fictional latin island. His father was british though. Media that follows the comics closely pretty much always portray him with that accent, TAS, Young Justice, most if not all of the animated movies,etc. In the commentary for Dark Knight Rises it's stated that they wanted his accent to have an ancient latin type of vibe rather than latin american so he may even be of latin descent in that movie as well though it's hard to say since his origins were intentionally ambiguous.