The retroflex nasal is a type of consonantal sound, used in some spokenlanguages. The symbol in the International Phonetic Alphabet that represents this sound is 〈ɳ〉, and the equivalent X-SAMPA symbol is n`. Like all the retroflex consonants, the IPA symbol is formed by adding a rightward-pointing hook extending from the bottom of an en (the letter used for the corresponding alveolar consonant). It is similar to 〈ɲ〉, the letter for the palatal nasal, which has a leftward-pointing hook extending from the bottom of the left stem, and to 〈ŋ〉, the letter for the velar nasal, which has a leftward-pointing hook extending from the bottom of the right stem.
Its phonation is voiced, which means the vocal cords vibrate during the articulation. However, in some languages (like Swiss German) it can just mean that this consonant is pronounced shorter and weaker than its voiceless counterpart, while its voicedness or lack thereof is not relevant. In such cases it's more accurate to call such sounds lenis or lax.
It is a nasal consonant, which means air is allowed to escape through the nose, either exclusively (nasal stops) or in addition to through the mouth.
Because the sound is not produced with airflow over the tongue, the central–lateral dichotomy does not apply.