In Icelandic, the dental was originally a voiced dental fricative . It is preserved as such after vowels, voiced fricatives and but has been hardened to a stop after nasals and , and has been devoiced to after voiceless consonants and in some other cases (in most Old Norse texts, the alternation is already found in heavy roots, but the light ones preserve ). Furthermore, the voicing contrast between and has been replaced in Modern Icelandic by an aspiration contrast, which may not be realized phonetically in all the relevant positions.