Theme and Rheme
Theme and rheme help us understand how information is conveyed in clauses. Writers put the Theme first and this orients the reader to what is about to be communicated. The rest of the clause tells the reader something about the Theme and this ‘rest of the clause’ is called the rheme. New information, which is the focus of the message, usually comes at the end of the clause or sentence. Writers usually begin sentences by referring to information known by the reader (‘given information’, which is not always exactly the same as the Theme) and then add the new information. Writers use Theme and rheme to highlight information. The rheme in one sentence frequently becomes the Theme in the following sentence. For example,
New Zealand waters are overfished. This overfishing will have serious consequences...Theme is useful in helping students understand how to organise information at the sentence level.
More on Theme and Rheme: Theme as Constraining Force