THE HIERARCHY OF LINGUISTIC UNITS

FUNCTIONAL grammar relates grammatical categories to the communicative functions which they serve. These functions are seen to operate at different levels of organisation in the language, and may be identified in terms of the CONSTITUENT PARTS which go to form larger UNITS. This implies a segmental principle of organisation, in which larger units may be seen as being formed from smaller units, and smaller units being combined to form the larger units. For example, consider the unit WORD. e.g. books. This word is constituted from two MORPHEMES, "book" + "s". Together these two units make one word. Similarly, the word "eating" consists of two morphemes, "eat" and "ing". * Distinguish morphemes from phonemes. The latter identify units of sound as part of a pronunciation system, and which in themselves do not convey meaning, whereas a morpheme refers to a phoneme or combination of phonemes which has a particular meaning. Thus the word "cat" is a morpheme which consists of three phonemes, "ing" is a morpheme consisting of two phonemes, and "s" is a morpheme consisting of a single phoneme. (Remember also that a morpheme is not the same as a syllable). Words combine to form a GROUP. There are various types of group, each with their own characteristics and form which will be discussed later. The main groups are NOMINAL groups, VERBAL groups, ADJECTIVAL groups, ADVERBIAL groups and PREPOSITIONAL groups. The following examples will show what we mean by this, in which the separate groups are identified by obliques ( / ). (a) The sky / became / quite overcast. (b) The day / began / rather quietly. (c) The little children / are playing / happily / in the garden. In (a) we have a nominal group, a verbal group, and an adjectival group. In (b) a nominal group, verbal group, and an adverbial group. In (c) a nominal group, verbal group, adverbial group, and a prepositional group. The particular features of these groups will be discussed later, but we can make a few preliminary observations here. (i) In (a) and (b) the nominal groups consist of a noun HEADWORD (sky, day) and a pre-modifier (the), while in (c) there are two pre-modifiers in the nominal group - a determiner and an adjective (the and little). (ii) In (a) the adjectival group consists of an adjective HEADWORD (overcast) and a pre-modifier (quite). (iii) The adverbial group in (b) consists of an adverb HEADWORD (quietly) and a pre-modifier (rather). (iv) The verbal group in (c) consists of a lexical verb HEADWORD (playing) and an OPERATOR (are). (v) The prepositional group in (c) consists of a preposition (in) and a COMPLETIVE (prepositional object), which is itself a nominal group (the garden). * Note that the term "GROUP" is technical in the sense that it consists minimally of only one element. Groups then form the constituent parts of a CLAUSE, and clauses in turn form the constituent parts of a SENTENCE. Before going on to say more about these larger units, we should consider again how these units are related in terms of rank, as the following examples will make clear.
(1)	Dhea can't lift the boxes	(1 clause)
	Dhea/ can't lift / the boxes	(3 groups)
	Dhea / can't / lift / the / boxes	(5 words)
	Dhea / can / 't / lift / the / box / es	(7 morphemes)
(2)	The children played with their toys	(1 clause)
	The children / played / with their toys	(3 groups)
	The / children / played / with / their / toys	(6 words)
	The / child / ren / play / ed / with / their /toy / s /	(9 morphemes)
(3)	Go!	(1 clause)
	go /	(1 group)
	go /	(1 word)
	go /	(1 morpheme)
We referred above to the unit SENTENCE, and noted that the units which form the immediate constituents of a sentence are clauses. The above examples 1 - 3 each consists of a sentence which consists of a single clause. For the first part of this introductory series of units we shall treat the sentence as the largest unit, but this is to some extent an arbitrary choice since sentences do not exist in isolation as complete and self contained units, but do themselves form connections with other parts of larger texts. But consideration of the nature of these connections will be left for a later component of this course. For the present, then, we shall treat the sentence as the largest essential grammatical unit with which we shall be concerned. Thus, to sum up this very basic description of the rank scale, we may represent the simplest form of this in a hierarchy which may be viewed in two directions: from the top downwards i.e. from the larger units to their segmental parts (this is a CONSISTS OF relationship); or from the bottom upwards, i.e. from the smallest segments to the larger wholes (this is a CONSTITUENT OF relationship).