As far as my field of study is concerned, I want to share a presentation from one of our study sources. This is for the benefit of those who are studying the language. :D

1. THE BEGINNINGS OF
LANGUAGE DEVELOPMENT

2. Learning Language: the first words
It first becomes obvious that children are actually learning to
talk some time between twelve and eighteen months of age when
they begin to use single-word utterances of the following type:
juice
there
byebye
hi
car
hot
dada
no
big
shoe
look
up
biscuit
that
wassat
allgone
dirty
ball
Studies of child language development usually refer to these
one-word utterances as ‘holophrases’, implying thereby that these
single items carry a broader and more diffuse range of meaning
than do their equivalents in adult languages.

3. Some precursors of language development
THE INFANT CRY
From the moment of birth, for example,
infants can impinge dramatically on those
around them: they can cry. Indeed, from the
first weeks of life they have a repertoire of at
least three distinguishable types of cry – the
hunger cry, the pain cry, and a cry associated
with fatigue, boredom or discomfort – each
sounding subtly differrent from the other.

4. Some precursors of language development
THE INFANT CRY
The hunger cry, or ‘basic cry’ as it sometimes known, is a
moderately pitched loud cry that builds into a rhythmic
cycle made up of a cry itself followed by a short silence,
then an intake of breath followed by another short
silence before the next cry resumes the cycle.
The discomfort cry or ‘grumble’ is lower in pitch, more
variable in volume, though generally quieter than the
basic cry.
The pain cry is markedly different again, taking the form of
an inward grasp folloed by a high-pitched, long-drawnout rising shriek.

5. Some precursors of language development
FURTHER DEVELOPMENTS IN VOCALIZATION
The phase of ‘coing’ aroung three months and this gives
way in turn to a period of ‘babbling’ from aroung six
months onwards.
FROM VOCALIZATION TO COMMUNICATIVE
EXPESSION
One childe (reported in Halliday, 1975) fastened on the
sound ‘nanana(na)’ and used it to mean ‘give me my toy
bird’, he used a sound something like ‘buh’. While the
latter sound may be indirectly related to the adult word
for object, the other expression (‘nanana’) has no obvious
antecedent in the language (English) that this child was
taking over.

6. Some precursors of language development
THE COMMUNICATIVE FUNCTIONS OF
THE EARLY EXPRESSIONS
The kind of work being performed by these two
examples is primarily instrumental: they fulfill ‘I
want’ function for the child, serving satisfy
material needs and to gain the goods and other
services that are required from an immediate
situation. Other functions that emerge around this
time are the regulatory, the interactional and the
personal.

7. The early communicative expressions as as protolanguage
Babbling and vocal doodling fade out completely with the
advent of these functionally oriented expressions or
‘protoforms’. With others, babbling continues side by
side with the protoforms on into the development of
speech.
CONDITIONS THAT AID THE EMERGENCE OF A
PROTOLANGUAGE
The child is typically interacting predominantly with a
small circle of ‘significant others’, and the world of
persons and objects with whom and about which the
child communicates is usually relatively constant and
familiar.

8. The early communicative expressions as as protolanguage
EXPANDING THE PROTOLANGUAGE
Given special circumstances, the child is able to
accumulate expressions, thereby refining the distinctions
in meaning that s/he can make in each of the four
functional areas. For example, the child who produced
‘nanana’ at around nine months (see Halliday,1975)
continued over a six-and-a-half month period to
acuumulate roughly ten protoforms for expressing
instrumental purposes, adding expressions for meanings
such as
‘I want the clock’
‘I want some toast’
‘I want a rusk’
‘I want some powder’
to the basic two expressions that he began with in this
area.

9. From protolanguage to holophrases
Initially the holoprhases operate in similar ways to
the protoforms that cpomprises the protolanguage,
tending to slot into, and be an enactment of, one or the
other of the already established repertoire of functions,
be it the instrumental, regulatory, personal, heuristic,
intercational or imaginative function. Initially, then,
the holoprhases fit into the place alongside the
protoforms of the existing protolanguage. They do,
however, constitute a new departure for the child, who
now begins to assimilate expressions ready-made from
the speech of theos around him/her, instead of making
up protoforms afresh as s/he goes along.

10. Two-word utterances as beginning of syntax
The holophrastic phase has enabled the child to lay
down set of possibilities for doing things with
language – a functional basis, in effect, for later
developments. Now s/he must find ways for realizing
these functions not just in words but in the word
sequences that are such a crucial component of the
adult language system. In essence the child has to
develop a syntax; a way of combining single words
into sentences.