Modality is the selection of words used to express how definite we are about something. It can range from being uncertain (low modality) to very certain (high modality). It is used when discussing or writing about a point of view.

The purpose of a persuasive text is to convince the reader that a certain stance is better or to change their own perspective and to adopt the one that is being proposed. While this may be achieved through facts, evidence, statistics, anecdotes and expert opinions — how this information is conveyed is also very important. This is where modality comes in.

Low modality language implicitly conveys uncertainty. This will make a piece seem unconvincing to the reader as it would appear that the writer is either unsure about the topic they are writing on or that they are not fully convinced of the stance that they have chosen to take in writing their persuasive piece.  

In contrast, high modality language carries confidence and certainty with it. High modality words help to assert and emphasise facts. When utilised well they may even stir up strong feelings within the reader, making the reader more likely to be persuaded by the arguments being put forward.

Thus for persuasive writing it is recommended that high modality language is used throughout the piece due to its ability to help convince readers of the arguments being put forward and the certainty conveyed through the tone. Modality refers to a set of verbs that provide information about the degree of obligation or certainty involved in an action. While modality can be conveyed through the choice of words, sentence structure and grammar when ‘modality’ is discussed in persuasive writing for Kindergarten to Year 6, this is usually in reference to word choice of verbs. 

Modal verbs and expressions are often used when expressing an opinion or attitude about a possible fact or to control a possible action. They help to convey the presenter’s attitude towards the topic they are writing about. 

There are two main ways that modal words may be utilised. Firstly, it may be used to convey how certain something is in the past, present or future. It is used to predict or speculate about a fact, helping to measure degrees of certainty and possibility.

Secondly, modal verbs can also be used to control or direct action like giving or refusing permission, talking about obligations or necessities.