To any layman, ‘hearing’ and ‘listening’ may appear to be one and the same thing, but there is a subtle difference between the two words.
At one level, they are of course both functions of the ear that involve receiving sounds and processing them. However, herein lies the difference: any sound that is received by the ear and noted by the brain can be said to have been ‘heard’; it is only when a conscious effort is made to hear something that ‘listening’ comes into play.
For example, if the sounds from a conversation carry to you, but you make no effort to understand what is being said, you must say that you ‘heard’ the conversation. On the other hand, as soon as you make a conscious effort to understand or pay attention to what you are hearing, you are ‘listening’. Therefore, we do not ‘hear’ songs, we ‘listen’ to them (unless, of course, they are simply part of the background and we aren’t actually paying attention to them).
It must be noted that ‘hear’ can be used in place of ‘listen’ sometimes, but ‘listen’ should not be used in place of ‘hear’. For example, you may tell someone that you heard what he or she said, and it is understood that you were listening, ie, paying attention. You will learn these variations with practice in conversation.