TODAY is the final day of Book Week Scotland, a good time to reflect on the value of reading and writing.

Perhaps the most important message concerns literacy, education and equality. Recently, Dundee University blamed poor maths and science learning for difficulties in recruiting more pupils from deprived backgrounds into higher education. The were swiftly followed by St Andrews University having to defend the fact that it had granted places to just 14 applicants from deprived backgrounds last year, despite having an overall population of 7200 students.

In defending this lamentable figure, St Andrews vice-principal Stephen Magee made some good and some bad points. "We have a choice," he said. "We can continue to beat up our leading universities for failing to admit more kids from our most deprived areas, or we can start, without shame or blame, to ask if perhaps there is something going wrong throughout the whole equation."

St Andrews is one of the oldest universities in the world, and is characterised by The Times as the leading alternative to Oxford and Cambridge. It is right that the highest standards of academic excellence need to be attained by students who want to study there, and our school system should certainly play its part in providing all bright children, whatever their background, with the means to achieve these standards.

But it is also right that St Andrews, along with all other Scottish universities and colleges, should make more proactive and determined efforts to recruit talented students from deprived backgrounds. The intake figure quoted above suggests that there is a lot of work to be done. It is in fact a matter of shame, and collective shame too. There is considerable and consistent evidence in Scotland that children who do not enjoy a good start in early life are disproportionately disadvantaged when it comes to mastering the basic skills primary schools exist to teach, and secondary schools to refine.

This is both a social and educational problem, as the Government's Literacy Action Plan states clearly: "Literacy skills are linked to socio-economic status and level of deprivation, with those from more deprived areas achieving lower scores. In primary education, those from more deprived areas often fail to reach even basic standards of literacy. This continues into secondary, coming to the fore in the later stages of school-based learning. For example, S2 pupils from more advantaged areas are around twice as likely to perform above the expected level in reading." It continues by saying research has shown that in Scotland, socio-economic status is a more major determinant of attainment than in other countries.

The 2012 interim report from the Standing Literacy Commission, chaired by Sir Harry Burns, Scotland's chief medical officer, notes some of the consequences of this failure to educate: "If a person has low levels of literacy, they are more likely to suffer poor health; they are more likely to be living in poverty and deprivation; and they are more likely to be out of work or in unstable and low-paid employment."

It is not that Scotland lags behind the rest of the world in the overall literacy or educational tables. But the link between poor educational attainment and poverty seems to be more acute here than in most other countries. As many as 10,000 pupils leave the educational system each year without adequate qualifications and literacy and numeracy skills. Our educational system almost seems unwittingly to have been designed to penalise children from deprived backgrounds.

The reasons for this boils down to two essentials. First, those who do not have a good start in life, and who come from households where books and education are not prized, start school at a huge disadvantage. A recent academic study conducted over 26 countries demonstrates that having books in the home equips children with three years' extra education by the time they start school. Significantly, this is true for all children, regardless of socio-economic background.

Second, we begin to teach the basic skills of literacy and numeracy at far too early an age. Children as young as four or five are faced, as an introduction to school, with the complex task of mastering writing, reading and mathematics. There is compelling evidence that most children are simply not ready for it, neurologically or temperamentally.

As a result, they face an uphill task in mastering these basic skills, often toiling for more than two years to do so. Most children manage this successfully. But those from deprived backgrounds, who may have little home support for their learning, start even further back than most, and many will never catch up.

Those who disagree with this analysis, or who find it unpalatable, need to explain why the link between poverty and lack of educational attainment is so evident and so persistent in Scotland, and why in the world's best educational system – Finland's – children are at least seven years old before they are formally taught how to read and write.

The problems extend to every aspect of language teaching, from the development of the more sophisticated and nuanced skills that characterise an articulate person, to the issue of foreign languages. A recent British Council report highlights our underperformance in this area, despite ambitious Government targets. Very few children in Scotland are successful at learning a foreign language, something that seems quite natural to children in many other countries, and last week, the British Council Scotland complained that a "wholesale decline" in the study of foreign languages in schools and universities was hampering the nation's ability to trade with non-English-speaking partners. "Language learning is a vital component of being good global citizens," said director Lloyd Anderson, "and in an increasingly globalised and interconnected world, our young people and future workforce will be at a disadvantage if they lack language skills and cultural awareness."

There is no doubt that he is right, both in regard to foreign languages and English itself. But in order to raise attainment across the board, we need to clearly articulate exactly why skill with language is so important, and what the benefits are. We need to communicate this effectively to young people so that they become motivated learners. What might one say to them?

Let's start with the self-evident truth that writing well is useful in education. Even though allowances are made for language use in exams, expressing oneself well in this context is going to help gain marks. Creating a powerful and convincing argument isn't just about the actual points one makes; it is also about the ways in which those points are made, and how these are woven together to create a winning impression.

Language is a powerful tool of seduction which can be used to sway the hearts and minds of listeners and readers (exam-markers included). Which is why the study of rhetoric – the art of making a seductive and convincing argument in language – formed such an important part of education and public life in Greek and Roman civilisations, among others. And this is still vitally important today because human beings are naturally susceptible to well-chosen words. In short, ability with language places a certain kind of very welcome power in our hands.

It is also stating the obvious to say that the ability to write and express oneself well is key to future employability, especially with the jobs market so depressed and with graduate employment levels low. Surveys by CBI and Scottish Enterprise confirm that employers are constantly struggling to find employees with the advanced communication skills they need. Even at university and further education levels, many students are very poor indeed at expressing themselves accurately. At least one Scottish university employs a well-known writer as a remedial teacher of English (who is horrified by what she has found), while – as many college heads have told me – colleges are increasingly having to provide students starting further education with tutoring in basic English and grammar before they can get on with their actual area of study.

But writing and communicating well isn't just a question of employability or exam results. It reaches across every area of our lives. We might imagine that the modern world, which appears to be moving from the logocentric to one that is led primarily by the image, offers a considerable disincentive to writing. But the social and digital behaviour of young people suggests that they are writing a huge amount, and in a very public sense too – on Facebook, Twitter, in texts, emails and otherwise online.

The move to the digital world hasn't halted writing. Rather, it has increased the need for it, even if this writing has taken on new forms. And the interesting thing about all this writing is that it takes place in a social space which is increasingly used to define oneself and others, and where the detail of one's life and relationships, activities and interests is actively managed. If this is primarily where one presents and defines one's persona – one's social and professional self – then it follows that the ability to express oneself well is quite an advantage. Who are you? Are you funny, irreverent, intelligent, knowledgeable, original, unusual, inventive? Or are you dull? A lot of it is in the writing.

It follows that one must read widely, deeply, adventurously. The best advice that can be given to young people is that if one wants to write or speak well, one must read well. It is only in filling one's mind with the well-chosen words, phrases and rhythms of a good writer that one will learn. The process of discovering how to turn a phrase, structure a narrative or use language inventively and effectively is a process of imitation and digestion. Writing is a craft that is learned from others, and which is eventually made one's own through personal experimentation and exploration. By allowing us to encounter other minds that are greater and more original than our own, reading amplifies us.

There are many other advantages to reading well. Fiction is full of social information; it is where you can inform yourself about other people and how they might think, feel, reason and behave in particular situations. Fiction offers us case studies in human behaviour. This is useful in developing that most human of attributes, empathy – the ability to put oneself in another's shoes. It is difficult to overestimate the social and personal value of this, as one navigates one's way through life.

Parents have a leading role to play in supporting the development of a lifelong love of reading in their children, and this should start as soon as they are born. The advice here is simple: make sure there are books in the house. Register your child at your local library so that you can enjoy free access to books and to Bookbug song and rhyme sessions. Read with your children from the earliest age, and make sure that discussion about books and stories forms a part of your conversations as a family. Through stories, children learn to put themselves in the shoes of others, experiencing vicariously and safely whatever circumstance or dilemma is being played out in front of them, thus learning important social skills.

Nurseries and schools need to become much better at the early diagnosis of problems so that remedial action can be taken immediately. Schools need to develop a zero tolerance ethos towards illiteracy, but as we have seen from initiatives of this kind in places like West Dunbartonshire, parents must also be involved in order to achieve true success.

Finally, as children grow we need to help them understand that, however disengaged they are from politics, all this is about democracy and equality as well. Most people on the globe are not well educated. Most don't live in countries where free and individual expression of thoughts, feelings, ideas, or observations about people and society are prized or even allowed. Dictators shoot writers, and many writers have given their lives for the right of free self-expression, things that we rather lazily and decadently take for granted.

Taking part in a democratic conversation and process isn't just a matter of resting on one's rights as a citizen of Scotland, it's about exercising them. Democracy is about a lot more than just the vote. It is also about the voice.

So in the end it's very simple. Book Week Scotland celebrates reading, writing, books and our easy access to them through the public library system and organisations like Scottish Book Trust. Literacy is the passport to all of that. Books level the playing field. While we may never live in societies which are economically equal, we can at least provide equal access to literacy, books and their many benefits.

Marc Lambert is the chief executive of the Scottish Book Trust