The clip opens with the closing sound of chimes coming together which is a sound bridge from the previous scene, which is a non-diegetic sound. There is probably much more emphasis on this because no soundtrack has yet been established and the only sound other than the sound bridge is the dialog from the characters. The reason this has emphasis is because it shows the intensity of the awkwardness the room has in it, because essentially a business transaction is taking place, but one that is out of the ordinary.
A call girl who has experience in her work would be usually unfazed by clients, but the fact that this client is disabled means that there is an added sense of awkwardness, and the director has obviously decided that by not having a soundtrack to start the scene and instead only have the tail end of a sound bridge, followed by complete silence, not only adds the sense of awkwardness, but extends that awkwardness to the audience. He uses the sound to make the audience feel the same emotions or the same mood as the characters. If sound wasn't used then the effect would not be the same. If the clip had no sound at all, the audience would not capture the same feeling of awkwardness between the call girl and the disabled character.
The dialog used is swift and broken, often ending in unfinished sentences, simply because none of the characters are comfortable enough to finish them. The father of the disabled character cannot finish his sentence in particular, because he perhaps feels most uncomfortable as it is not a position that many fathers find themselves in. his sentences almost always are short or unfinished. This type of dialog helps build a perspective from the audience that even as the father, there is discomfort between father and son, something that may not have happened if the son was an abled person.
There is then an ambient sound made where the callgirl collects an envelope from the client and the rustling sound that is made makes some suggestion that the sound has been enhanced. This diegetic sound could be used to show how silent the room is between dialog, almost like you could cut through the tension with a knife.
When the dad is sent down to the car to wait, the call girl attempts to lock the door, and it is the diegetic sound of the door locking that triggers the disabled character to show discomfort and the call girl realises this. The sound of the door locking, reflects the disabled characters vulnerability and shows how much he relies upon his dad. He needs the door unlocked so that his dad can just walk in at any moment he needs help, but the thought of having the door locked means he is alone, and this scares him.
The scene then shows the father in the car, and the sound shows his anxiety, by hearing the window moving up and down, him moving his chair backwards and forwards and sounding the horn. These sound affects represent the father’s anxiety at leaving his disabled son upstairs, probably giving him independence for the first time. But the sound affect that is probably most representative of this is the music that comes on. Classical music is played through the radio and the father switches it off straight away. this is because classical music is quite a happy tune, in line with peoples mood that are quite happy and harmonious, but the fathers emotions reflect that of a nervous, anxious person and the classical music doesn't fit with that representation so he switches it off straight away.
The final scenes introduce a soundtrack that is headed by the use of a harmonica, an instrument usually associated with the blues, which represents quite sad music. The soundtrack begins when the dad is in the van, and is carried over into the next scene back in the room, where the call girl and disabled character have finished their glasses of champagne and become slightly more intimate together. The use of the harmonica is shown not to be a representation of sadness, but rather to give sympathy to the disabled character. It is a slow and light tune, used to make you feel sorry for the boy and sets the atmosphere of the room.
It is therefore shown that the uses of sound in this clip are used to show awkwardness and sympathy towards this character, and that this is the main aspect of this clip. Without these compilations of sounds it is easy to say that the same effect would not be imposed on the audience and that the same sense of atmosphere and emotion shown would not be received by the audience.