It happens in Irish a lot: you run into silent letters all the time (and dh in the end of the word is almost always silent). On top of that there are regional variations - some dialects pronounce certain letters while others don't. There are rules and reasons for why all these letters are there (for example e after d affects the quality of the consonant), but my advice would be to just learn the words as well as you can based on the recording, unless you are interested in minutia.
dearcadh really does carry the "vision" meaning of "point of view".
While we sometimes use "attitude" and "point of view" in similar situations in English, "attitude" also implies behaviour, so it's not a good translation for dearcadh - it might work in some specific contexts, but not in general.