What is the purpose of a signal phrase?

The main objective of a signal phrase is to highlight and/or differentiate the author´s ideas in a text from the cited source´s ideas.

Explanation:

A signal phrase is a concise and short clause that helps to paraphrase, summarize or to introduce a source of information.

we use signal phrases for three main reasons:

1. In order to establish boundaries. They help us to highlight boundaries between the author´s words and the source´s words.

2. To give importance to the source. Signal phrases are important to call the reader´s attention over a well-known author. Signal phrases are used too as a literature review.

3. Signal phrases help us to avoid plagiarism. It is important to cite source material. And, to have in mind special formatting citations depending on the citation style that we are applying.

They may include specific information like the author´s name, job title or background. Signal phrases mainly appear at the beginning of a sentence and not after to mention the source material. It is possible to find them too in the middle of a source or even in the end.

There are certain verbs to use in the signal phrases. The right selection of them may depend on the way we are using a source. For instance: Acknowledges, Claims, states, suggests, etc.

Here is an example of a signal phrase:

According to Bajtin (1980) ...

that a few simple words can whet the mind's appetite to further explore.

the reason some people sacrifice their own life for another person's life could be that they are in love with them and would do anything to keep them safe a protected even if that means risking their life in the process