This study, devoted to Alban Berg’s lied op.2 n°4, looks upon the meaning of the exclamation « Horch ! » in the musical composition : what is being heard ? who is being called ? why is it related to memory, pastoral lyricism and, more specifically, to the conventional image of the nightingale ? After the appearance of idyll, the evocation of loneliness : Berg’s lied actually contains a second meaning, based on symbols (letters, numbers) which are related to the composer’s identity and to the name of Arnold Schoenberg, to whom the lied seems to be principally dedicated. Reading Berg’s musical text consists not only in deciphering the implied meaning - not secret, in this case -, but also in connecting it with its more evident content : « Horch ! » is a call for interpretation.