This document discusses extending the system of traffic lights to convey more meanings through variations and combinations of lights. It introduces systems that use a pink light or flashing red to encode new meanings like "reverse" or "do a U-turn" without needing additional lights. The document then discusses how language differs from such a system in its ability to convey an infinite number of new meanings through creative use of a finite set of expression units. It outlines some of the key principles of grammatical analysis for understanding how language organizes its lexicogrammar to exploit this creative potential.

1. Introduction to the lexico-grammar

2. The traffic lights revisited: extending the system
• The lexico-grammatical level was described simply as an intermediate level of
linguistic coding.
• We must now consider in more detail what the function of this level is. What, for
example, does it allow us to do in language that we cannot do with a two-level
semiotic system like the traffic lights?
• For example, we could introduce a PINK light to encode this new meaning, giving
us System 5.1
• To economize on the number of coloured lights we need to use, we could start using
variations or combinations of expressions to realize new contents. See, for example,
the realizations in System 5.2

3. - Reverse = PINK
- Stop = RED
- Slow down = AMBER
- go = GREEN
Content encopded in expression
( meaning ) (realized in) (realization)

4. • stop RED
• slow down AMBER
• prepare to go AMBER & GREEN
• Do a U-turn FLASHING RED
• Go GREEN
System 5.2 Combining in the traffic ligh system

5. The demands we make of language
• However, with the semiotic system of language, we want to make more
meanings than that. In fact, the amazing demand we make of language is that we
want to use it to mean anything at ail — to make an infinite number of meanings.
Language meets this demand, in that it has an unlimited creative potential. That is:
1. language allows us to mean new things:
you can say things that no one has ever said before, and you have no trouble
understanding things that you have never heard before. So, while you could never hope
to have heard every sentence it is possible to say in English, you will have no difficulty
understanding any English sentence said to you (provided it conforms to the
conventions of the system of English)
2. language allows us to mean anything: it is very rare that, as a speaker of a language,
you would come to a point where all of a sudden you cannot make the meanings

6. Principles of grammatical analysis: units and constituency
• Having established that it is the lexico-grammar which gives language its creative potential,
we will now focus on how the lexico-grammar is organized so that its creative potential can
be exploited.
Grammatical constituents: the rank scale
• Although we have now identified the meaningful units ranging from largest to smallest that
realize our passage, there are certain problems with using the listing above as our set of
grammatical units.
• The first problem is that the unit the text does not belong in the lexico-grammatical rank
scale. Text, as was discussed in Chapter Four, is a semantic unit and not a lexico-grammatical
one. The relationship between text and everything below it is not one of constituency but one
of realization.
• A text is not something that is like a sentence, only bigger, it is something that differs from a
sentence in kind. A text is best regarded as a SEMANTIC unit: a unit not of form but of
meaning. Thus it is related to a clause or sentence not by size but by REALIZATION. A text
does not CONSIST OF sentences; it is REALIZED BY, or encoded in, sentences.

7. • One way to understand this difference between text and sentence is to consider how a
sentence-by-sentence description of the text would fail to describe its texture.
Bracketing
• To this point, we have suggested the purpose of a grammar to make infinite meanings from
finite expression units, and to make meanings simultaneously.
Embedding or rank shift
Very early in your bracketing career you will discover that sometimes a clause constituent seems
to be a complex structure in itself. The case of the prepositional phrase considered above
highlights one of the main complexities that bracketing can reveal, one that is important in
understanding the structure of clauses. Consider how you would bracket the following clause, for
example: All students who are completing this year must submit their final essays
If you apply the probe, substitution and movability tests suggested above, you will have no
trouble identifying the verbal group (what must they do? they must submit) and the final nominal
group (what must they submit? The final essays). However, when you probe the first part of the
clause with the who' probe, you will find that the answer appears to be a very long nominal group
all students who are completing this year.

8. • As you will have realized as you study these examples, embedding is a way of boosting the
content of a clause, by exploiting the clause's potential to recycle through the tanks. Once you
have learnt to recognize embedding, then it need not present you with any problems.
However, as systemic linguistics treats one kind of embedding slightly differently from many
other grammatical models, one further explanation is necessary.
Labelling
• However, bracketing on its own is a very limited tool in grammatical analysis as it does not
really tell us anything more about the structure than we already knew.
• Priority to functional labelling: although both class and functional labelling of constituents is
essential in a comprehensive description of the clause, we will concentrate on exploring
functional labelling and its implications, leaving class labels in the background.
Multifunctionaltty of clause constituents