You might think that teaching children to use capital letters is “so simple it doesn’t even seem worth looking at”, says Nenagh Kemp, an associate professor in the School of Psychological Sciences at the University of Tasmania, Australia.

That’s because, in English, capital letters are used in two straightforward scenarios: at the start of a sentence or for a proper noun.

“But it’s been three years of finding out that it’s not that simple at all,” says Kemp.

Kemp and colleagues, Emilia Hawkey and Matthew Palmer, have carried out new research into how children learn to use capital letters, with useful findings for classroom teachers.

Capitalisation provides a particularly interesting window into how children understand and use grammatical rules, says Hawkey. While so many such rules have obvious exceptions - just consider the classic “I before E except after C” - capital letter use is one of the few “where there aren’t meant to be any [exceptions]”.

So, in theory, Hawkey adds, “once you’ve been taught the rule, if you understand it, you will use a capital all of the time when you should use it and none of the time when you shouldn’t”.

Capitalisation isn’t that straightforward

But the regularity with which capital letters are misused in public life - be that in corporate presentations, advertising campaigns or on restaurant menus - clearly shows that capitalisation isn’t as straightforward as the rule makes it seem.

So what is going wrong?

By carrying out writing tasks with primary and secondary pupils and university students, the research team found they were more likely to use capitalisation correctly when there were two “clues” to draw on in a sentence, rather than just one.

For example, if a proper noun appears at the start of a sentence, pupils are more likely to capitalise it correctly than if a proper noun appears in the middle of a sentence, or a common noun appears at the start.

“The more information you have pushing you towards this rule decision, the better,” says Kemp. This works against the idea that once you’ve learned the rules, you will always capitalise correctly. “The fact that both [clues] work better than one suggests it’s not just rule application. It’s about thinking what you’ve seen in the world, following that and gradually building up knowledge.”

It’s important, therefore, that teachers don’t assume that simply getting children to commit the rules to memory is enough. But what else should they be doing?

Regular revision of capitals

There is no mention of capital letters in the English national curriculum after Year 2, which Hawkey says is similar in Australia.

“We argue that it would be really beneficial to have a formal revision of [capitalisation] rules in the following years in primary school,” she says, with recaps throughout secondary, too.

Although many teachers might already be doing this as a matter of course, making it an explicit part of the curriculum would prevent it from being squeezed out by other content.

Regular revision of capital letters would also help to develop other grammatical skills, Hawkey adds, “because capitalisation itself provides an interesting window into other foundational language processes, like understanding the structure of a sentence and understanding the meaning of a word and the role it plays in a sentence”.

In addition, Hawkey says that after teaching the rules, she would advise teachers to draw attention to capital letters as much as possible during everyday classroom activities, being intentional about mentioning the reasons for using them.

For example, a teacher might say: “Today, during your silent reading time, when I say ‘pause’, have a look at the page, find five capitals and write down why they have a capital.”

This can take place beyond literacy lessons, too. “Walking to a music class or a physical education class, a teacher might point to a poster on a wall and say: ‘This one has a capital and this one doesn’t. Why is that? Can anyone tell me?’”

Learning spellings in context

Kemp adds that, where possible, spellings should be learned in the context of sentences, particularly when different versions of the words might lead to one being capitalised and one not. For example, learning when to capitalise the name Lily as opposed to the flower makes more sense when a child learns to write “I saw lilies growing in the garden” and then “I saw my friend, Lily”, rather than learning to spell the words in isolation.

She adds that spelling tests - which traditionally test individual words - could also incorporate whole phrases or short sentences to aid this contextual learning.

Importantly, this is not just something for primary staff to focus on. As Kemp points out, “no matter what age group, up to the third year of university, 10 per cent of words were incorrectly capitalised” during the study.

Kemp suggests that some more nuanced examples might best get older students thinking about capitalisation. For example, the word “aunt” becomes a proper noun, so is capitalised when speaking about a specific relation - “my Aunt Joan” - while “my aunt who lives in London” does not require a capital.

Similarly, “Prime Minister Keir Starmer” is capitalised because the title functions as a proper noun when referring to a specific person, while more generic usage - such as “past prime ministers” - does not.

Importance of good grammar

Careful teaching of the basics is perhaps more crucial than ever, suggests Kemp, as digital communications have made it more typical to omit capital letters altogether - meaning that young people might now struggle to see their purpose.

But correct capitalisation is still a “shibboleth”, Kemp says, “a marker of intelligence or correctness”, which, for example, sends signals to examiners and may affect the grade they give to a candidate.

Whether someone is applying for a job, using a dating app or responding to an advert for a housemate, research shows that grammar is something we subconsciously notice and judge others on.

Getting capitalisation right clearly matters in real-world contexts, then. Helping pupils to recognise that will be a useful place to start.

You can now get the UK’s most-trusted source of education news in a mobile app. Get Tes magazine on iOS and on Android