Music in general and songs in particular help to resist sorrows with more composure. Dreams, in this case, invite you to use these elements to sublimate the misfortunes and to share the joys. If you forget the lyrics or go out of tune it may be warning you to avoid dismissing the difficulties of a task that will begin shortly. Of course, what we sing (either something with rhythm, sad, funny . . .) is greatly important because it will give you a very reliable clue of your mood in real life. If it is a song you learned in childhood, perhaps it refers to an old problem or inhibition. Humming while you sleep is, however, a sign of grief; your inner self is lulling you in order to calm you with a soft melody. Although, in general, songs are a prediction of serene happiness, to listen to someone singing promises safe businesses.