To understand a lecture or talk, it is not enough just to understand the important information in each sentence. It is also necessary to understand how the sentences are related to each other. Every text has a structure. It is not just a random collection of sentences. The parts that make up the text are related in a meaningful way to each other. Recognising the way in which a text has been organised will help you to understand it better. In order to understand the text, it is necessary to understand how the sentences are related. Words like "it", "this", "that", "here", "there" etc. refer to other parts of the text. You need to understand these connections or links.
Look at the following text:
1. The implications of - er - von Neumann's concept of the computer were, first of all, that one needed a large internal memory. Erm - you had to store data that you weren't actually operating on. You'd got to staticize it and keep it in a store.
The highlighted "it", in this case, refers to "data".
There are four main types of links used in academic texts: reference, ellipsis and substitution, conjunction and lexical cohesion (Halliday and Hasan, 1976).
Certain items of language in English have the property of reference. That is, they do not have meaning themselves, but they refer to something else for their meaning.
2. In this country, unemployment benefit is provided through the state. In Sweden and a number of other European countries it's provided either by the state in conjunction with the Trade Unions, or through the Trade Unions, elsewhere employers' associations play a different role.
In this text "it" refers to "unemployment benefit". In order to understand the text, you need to know what these words refer to in the text.
3. Now, the concepts and ideas which we get from a study of Mechanics - things like force, work, energy and so on - are things that keep occurring when we try to interpret physical phenomena, and therefore some understanding of them is essential if we're going to make headway in any study of Physics.
4. That, left to its own devices, a body continues in a state of rest or of uniform motion in a straight line, assuming there are no external forces such as the force of gravitation acting on it.
Other words used in this way are "he", " him", "it", "this", "that", "these", "those", "here", "there" etc.
Substitution is the replacement of one item by another and ellipsis is the omission of the item. If speakers wish to avoid repeating a word, they can use substitution or ellipsis.
5. But essentially in a digital computer, we do things serially, one operation at a time. And the original reason for that was very much a reliability-based one.
Here, "one" means "reason". The speaker has substituted "reason" with "one". Other words that can be used are "one", "ones", "do", "so", "not".
6. From thence, logically, to nitrogenous excretion, and then finally, we will jump rather, and consider, in the last couple of lectures or so, problems of buoyancy in marine animals. Erm, rather different from the other ones that we've considered but, as I hope you'll see, again, homeostatic mechanisms are at work.
Ellipsis is substitution by zero.
7. The laws he formulated are now known as Newton's Laws of Motion. There are three laws. The first is that every body - a body is a material object of any sort in this term - every body continues in a state of rest, or of uniform motion in a straight line, unless it is acted upon by a force.
"The first" means "The first law".
8. Well, federalism is a system of shared governmental powers, and Reagan, summarizing the various scholars who've worked in this field, identifies six main features of federalism, which together add up to what you might call classical federalism. Firstly, there is a constitutional division of governmental functions, each level being autonomous in at least one sphere of action. So an obvious sort of division, under a federal system, would be defence responsibilities in the hands of the central government or federal government, with education being a state or local responsibility. Secondly, each government is final and supreme in its constitutionally assigned area. Thirdly, both levels act directly on the citizens. Fourthly, both levels derive their powers from the sovereign, from the people or the constitution, rather than from one another. Fifthly, therefore, neither can change the relationship unilaterally, and finally, such systems normally have regional divisions. The states exist as of their own right.
"Neither" means "neither level of government".
Conjunction shows meaningful relationships between clauses. It shows how what follows is connected to what has gone before.
9. And in 1929, the American physiologist Cannon coined the term, 'homeostasis'. 'Stasis', as in static, 'homeo', the same, and therefore it really means 'remaining the same'. Homeostasis. Now what Cannon actually wrote was this. Erm, 'The constant conditions', 'The constant conditions which are maintained in the body might be termed 'equilibria'.' So, in other words, this constancy you could call 'equilibria'.' 'That word, however, has come to have fairly exact meaning as applied to relatively simple physico-chemical states. In closed systems, where no forces are balanced.' So in other words, he's saying that you could use the term equilibrium, but really equilibrium tends to be concerned with such things as chemical equations, chemical reactions, and he wants to use another term which perhaps has less overtones to it.
The words "therefore" and "so" are used to show that the lecturer is giving reasons. The word "however" shows that this statement is opposite to the ideas that have come before. Other words used are "for example", "as a consequence of this", "firstly", " furthermore", "in spite of this", etc.
This is a way of achieving a cohesive effect by the use of particular vocabulary items. You can refer to the same idea by using the same or different words.
10. The laws he formulated are now known as Newton's Laws of Motion. There are three laws. The first is that every body - a body is a material object of any sort in this term - every body continues in a state of rest, or of uniform motion in a straight line, unless it is acted upon by a force. That's Law One. That, left to its own devices, a body continues in a state of rest or of uniform motion in a straight line, assuming there are no external forces such as the force of gravitation acting on it. Law Two: when a force acts on a body, the rate of change of momentum - the rate of change of momentum - is proportional to the magnitude of the force, and takes place in the direction in which the force acts. Then we have the third law, which you will remember is normally simply stated as 'action and reaction are equal and opposite'.
11. If you've done any biology at all, of course, you'll realize that every living organism is a machine. Some such machines, such as unicellular plants and unicellular animals, such as amoeba, are very simple. On the other hand, you've only to consider the functioning of, say, an insect, or a mammal, or a flowering plant, to realize that it is extremely complex.
For cohesion to occur, it is not necessary for each word to refer to exactly the same item or even be grammatically equivalent. All the words related to computers contribute to the cohesion.
12. Erm - one change which one doesn't normally think of is in things like domestic applications of computers. Erm - you tend to think of that as a kind of low technology area. The one really vital thing in any home equipment, domestic equipment, is reliability, because whereas in, if you're going into industry, you can have service mechanics around, you can actually have a piece of equipment that does need a continuous attendance, if you're selling into a domestic market, low cost doesn't just mean low cost of the thing you originally sell, it means continuing low cost of servicing it. You want the kind of thing that is reliable enough, that it lasts long enough for people to throw it away when it finally breaks down. And so it's only been recently that both cost and reliability have got to the kind of level where people are now talking of - erm - computers in the home, game-playing systems, putting them into television sets, putting them into washing machines and so on. We're getting down to a kind of level of use which is obviously remarkably different from a, a big central machine doing payroll work. There's an enormous spectrum of applications of computers.
Other forms of lexical cohesion commonly used are "repetition", "synonyms" and "near synonyms", "collocations", "super/sub-ordinate relationships" (e.g. fruit/apple, animal/cat) etc.