During the toddlerperiod children develop the capacity for symbolic representation, the use of ideas, images, etc. to stand for other objects. Children's representational abilities become obvious in their development of language, an abstract, rule-governed, system of arbitrary symbols that can be combined in countless way to communicate information.

• Sounds, Structure, Meaning, and Conversational Rules
1. Phonology - sounds of a language.
2. Semantics - meanings of words.
3. Morphology - grammatical endings.
4. Syntax - sentence structure.
5. Every language has its own set of phonemes--speech sounds that contrast with one another and can change the meaning of a word.
6. The smallest meaningful units in a language are called morphemes.
7. Pragmatics is the set of rules governing conversation and the social use of language; it includes knowing how to use language to accomplish social goals. Children learn appropriate social use of language both from their own experience and from explicit teaching by others.
• Productive and Receptive Skills
  Children need both productive skills and receptive skills to carry on a conversation. The development of receptive skills tends to run slightly ahead of the development of productive skills.

• Learning the Sound Patterns of a Language
1. Mastering sound patterns of a language can be difficult.
2. The early period of prelinguistic vocalization during the first year of life can be divided into five stages:
• Crying - first weeks of life.
• Cooing - around 2 months; sounds expressing pleasure and contentment.
• Vocal play - around 4 months; produce sounds that vary greatly in pitch and loudness.
• Canonical babbling - around 6 months; make speech-like sounds, strings of syllables. Environmental input for language is quite important at this stage.
• Conversational babbling or jargon - around 10 months, most children start to make the transition from babbling to true speech, and a few protowords may appear.
3. Two things are needed to prepare children to begin speaking:
• Must gain control over their speech apparatus to produce speech sounds intentionally.
• Must learn the phonemes of their particular language by paying close attention to the speech sounds they hear and begin imitating them.
• Learning Words and Their Meanings
1. First Words
• Many children say their first clearly identifiable words around their first birthday, although there is great individual variation. First words are usually for familiar persons, objects, and routines and may also be for expression of feelings, movement, and social commands.
• Some children use their first words mainly to refer to objects and events (referential style), while others use them mainly to express affective or social routines (expressive style). Mothers of referential children often encourage labeling vs. the directing of children's behavior more common with expressive style children.
2. Vocabulary Growth
• Average vocabulary for 18-month-olds is 50 words, then there is a dramatic vocabulary increase (vocabulary spurt).
• Referential children have more obvious vocabulary spurts.
• Average productive vocabulary = 8,000 to 14,000 words for the average 6-year-old.
• Children's receptivevocabularies are considerably larger than their productive vocabularies. Between ages 1 and 6, the average child is learning an average of 5.5 new words per day (40,000 words by age 10 or 11).
• Timing and rate vary, with SES influencing both.
3. Processes of Word Learning
• Words are used before the concept of words is grasped. At around the vocabulary spurt, children begin using words to refer to categories of objects, etc. Learn everything has a name.
• Children's first task in learning words is to extract them from the stream of speech they hear,4444 which leads to some segmentation errors (e.g., "readit the book").
• By age 2 children can use fast mapping to make a quick guess at a word's meaning in context.
• Fast mapping is aided by joint attention - the tendency for language-learning children and their adult conversation partners to share a focus of attention.
• Fast mapping can work only if children have built-in assumptions about the most likely meaning of unfamiliar words, using the whole-object assumption. It is the tendency to assume that unfamiliar words are names for objects rather than for attributes or actions.
• Children tend to assume that unfamiliar words do not refer to things for which they already have labels, an assumption known as lexical contrast.
4. Errors in Early Word Learning
• The most common semantic mistakes are errors of underextension (too restricted use of a word) and overextension (too global of a word use).
• Underextensions are less obvious than overextensions, which are very common when a child is beginning to build a vocabulary and become less frequent as more words are learned.
• Children may knowingly overextend because the word used is the closest they have for what they wanted to say. Receptive vs. productive overextensions.
• Learning Morphological Rules
1. Children's first words are usually single morphemes. A language's grammatical morphemes (units of language that change the meanings of words and sentences) are gradually added.
2. Order of Acquisition
• First children add -s to nouns and -ing to form present participles.
• Later they used -ed to form past tense verbs and -s to form the third person singular. The last to appear are those for contractions of the verb to be.
• Order depends on grammatical complexity, semantic complexity, and phonological characteristics.
3. Productivity and Overregularization
• Morphological development provides clear evidence that language development involves rule learning--for example, in children's overregularizations of English past tense and plurals.
• Overregularization is an example of what developmentalists call a growth error--an apparent setback that is actually a sign of a more advanced way of thinking. These errors provide insight into the cognitive processes underlying language development.
4. Learning to Form Sentences
• In any system of syntax, individual words belong to particular form classes, such as nouns, verbs, and adjectives. Syntactic rules specify how words belonging to various form classes can be combined to make phrases, clauses, and sentences. Form classes are highly abstract, and cannot be learned simply by noticing how specific words are used and then figuring out a rule for each word. Instead, children somehow extract and use rules involving these abstract categories from the particular, concrete examples of speech they hear.
• An important feature of syntactic rules is their productivity.
5. The One-Word Stage
• When children first begin to speak, they use only one word at a time.
• When these words are used to communicate a more complex meaning, they are said to function as holophrases (a word that conveys extended meaning–"Mama" = "I want my Mama.").
6. First Sentences
• At 18-24 months, toddlers start to put two words together, tied into the appearance of verbs in the child's vocabulary. At first these combinations are probably not true sentences. When true two-word sentences appear, they usually take the form of telegraphic speech, as few articles, conjunctions, or prepositions appear.
• Categories of meaning in telegraphic speech are quite similar across languages.
7. Further Syntactic Development
• As children's sentences grow longer, they also become more grammatically complex.
• Roger Brown divided early syntactic development into five stages, based on utterance length, from 1 to 4 morphemes. Most children pass through Brown's five stages by the time they reach age 3 _.
• Learning to Use Language Socially
1. Children also are learning how to use language socially (pragmatics). Are acquiring linguistic andcommunicative competence. Linguistic competence involves syntactically and semantically correct use of a language.
2. Communicative competence involves being able to carry on conversations, repair breakdowns in communications, and to use language in socially appropriate ways (as determined by culture).