Phonology
Icelandic has very minor dialectal differences phonetically. The language has both monophthongs and diphthongs, and consonants can be voiced or unvoiced.
Voice plays a primary role in the differentiation of most consonants including the nasals but excluding the plosives. The plosives b, d, and g are voiceless and differ from p, t and k only by their lack of aspiration. Preaspiration occurs before geminate (long or double consonants) p, t and k. It does not occur before geminate b, d or g. Pre-aspirated tt is analogous etymologically and phonetically to German and Dutch cht (compare Icelandic nótt, dóttir with the German Nacht, Tochter and the Dutch nacht, dochter).
Read more about this topic: Icelandic Language