There are a couple of key themes worth considering in a discussion of Beckett's radio play Words and Music, written in 1961 and broadcast the following year. (Let us be sure not to confuse these with the themes and subthemes within the narrative itself: in the play, Croak, the main character, proposes several themes for the diversion of the small party, like Love, Age, the Face, and so on. However, I do not think that is what you are asking about. I believe your question is about Beckett's themes, not the character's proposed themes in the story.)

Let us talk about some of the important themes that this play brings up.

The elements of consciousness

The concept of the play, in part, is that Croak invites two minstrels, Joe (Words) and Bob (Music)—two characters who are often at odds—to entertain him in the hope that they will become friends. You could say that there are three characters in the play.

Some critics hold that these "characters" are only symbolic. They represent different parts of human consciousness. All of us, as human beings, have many different elements to our own consciousnesses—we have different ways to process information and different ways to express ourselves. There is a part of the brain that ignites when you are listening to classical music or walking through an art museum that is different than the part you might use when having an in-depth conversation with a friend, for instance. Beckett plays with this idea in the play, leaving us to wonder whether Words and Music are actual people or whether they are figurative.

The fallibility of man and the struggles of a creative life

Croak ("the poet"), our main character, despairs at his inability to create all of the art he dreams of. He can hear music in his head, but he cannot necessarily translate that beauty to the page.

He has tried and occassionally failed to write the way he wants to. He chides himself for his weakness, and he challenges (and even bullies) Words and Music—an expression of his own frustration.

The challenges of self-expression

We cannot express ourselves in words alone. Words are never enough. This is a theme that runs through Beckett's canon. Words are sometimes too much, and other times they can not be enough.

Music wins over Words in this play. Beckett has talked about this in interviews, and he has dealt with this theme in many of his works: there are ideas that cannot be spoken or written, and there are concepts so ephemeral that they are better expressed in musical form.

What do the characters symbolize in Beckett's play Words and Music?

Words and Music is seemingly a play that is ultimately about the creative process. The play truly consists of three "characters," though the word can only be used loosely, since the play is entirely aural, and one of the "characters" is literal music (sometimes referred to as Bob).

The other two characters are Croak and Words (spoken poetic words that are sometimes referred to as a character named Joe). Once again, since the play is a radio play and is an aural experience, there is no physical manifestation of any of the characters.

Croak is a symbol of the artist, any artist, perhaps Beckett himself. Frequently referred to as "my lord" by Words, it can be surmised that Croak is the master, ruler, or creator of Words.

Words, quite simply, symbolizes language. Beckett, being a poet and playwright, frequently used words and consequently needed to gather an understanding of them. Croak attempts to command Words, to no true avail.

Music, then, symbolizes music, or another aspect of the creative process. While Words attempts to convey a thought, Music's interpretation of the same thought is often conflicting. It's worth noting that the musical numbers for the radio play were composed entirely by John Beckett (who is, quite interestingly, Samuel Beckett's cousin). Thus, Music can be seen as an alternate form of the artistic expression, or even the viewpoint of another artist.