1.2.4. Vowels in context

It is important to note here how vowel features are affected by coarticulation with consonants and with other features of phonetic context. Length is especially susceptible to the following circumstances:

• vowels are longest in an open syllable, they are shorter in a syllable closed by a voiced consonant, and vowels are the shortest in a syllable closed by a voiceless consonant: cf. sea, seed, seat, sigh, side, sight; as a result, the so-called "short" vowel of Ш may be longer than the "long" vowel of beet;

• vowels are longer in stressed syllables than in unstressed ones: cf. bil­low, below— ['bitao], [bi'tau];

• vowels are longest in monosyllabic words, they are shorter in two-syllable words, and shortest in the words with more than two syllables: bid, bidder, forbidden, read, reader, readable;

• the vocal folds activity may be affected, thus producing a reduced voiceless vowel after a voiceless stop, as in the first syllables of the words potato, catastrophe;

• vowels may be nasalized before a nasal: man [maen];

• vowels are retracted before a word-final velarized /1/: bell, sill.

To sum up the features of vowel articulations which depend on coarticulation with the neighbouring consonants we can conclude that English vowels are normally affected by consonants which follow them. This rule concerns variation in length, nasalization and velarization. In American English it also concerns retroflexion of vowels before r.

The influence of the prosodic features of stress upon vowel length appears to be universal, common with many other languages of the world.

Vowel variants in particular phonetic contexts are discussed in Part II. Phonology.

1.3. Language acquisition: how speech sounds are learned

Intonation patterns are the first kind of linguistic structuring in the vocalizations of the child; they emerge as early as 6 months. Children appear to perceive intonational differences before differences in phonetic segments, discriminating intonational rise and fall contours in adult English speech by 8 months. In terms of production, by 8 months distinctive intonational contours of rise and fall can be detected in child's output. Though these early intonational patterns are not the same as fully-formed adult patterns, they may reflect their general characteristics and often signal differences in meaning. The acquisition of Chinese tone (4 distinct Mandarin tones) occurs well in advance of the mastery of segmentals, and within a short period of time. Just as tones are stored as part of the identity of the word in Mandarin, so also are stress patterns in languages like German, English, and Russian. For example, the stress difference between 'permit and permit is stored away as part of the underlying representation of these two words (Kess 1992:309-314).

Classifying consonants by the place of obstruction we proceed from the lips through the oral cavity to the larynx. Classifying by the manner of articulation we begin with the stops, then to fricatives and affricates. It was found that babies start practising sounds of their mother tongue when babbling in a similar order. There is a lot in common in sound acquisition among world languages. The order of acquisition of classes of sounds goes by manner of articulation: nasals are acquired first /m, n/, then stops /b, d, k/, liquids, fricatives and affricates. Classes characterized by place of articulation features also appear according to a certain order: (bi)labials, velars, alveolars and palatals.

The early babbles consist mainly of repeated consonant-vowel sequen­ces like mama, gaga, dada. Thus the first consonants are /b, m, d, k/, the first vowels are /a/ and /i/, the first syllables are of the consonant-vowel (CV) type, the basic rhythm is syllabic. (Even at a later stage American and English children stress form words and prepositions). The first meaningful contrasts are expressed intonationally: a high rise-fall of demand and a level (rise-fall-)rise of content.

All the children go through the stages of first babbling, then one-word period, then constructing sentences (telegraphic style). It is amazing that they do it so quickly: children do not seem to learn language, they "pick it up", and a five-year-old child can talk as well as an adult. A child can learn any language of the world he/she is exposed to. When and how do language-specific features occur?

At the age of 6 months the baby begins practising only the sounds which are contrastive (phonemic) in his own language. Thus, for instance, be­fore that age a Japanese baby can distinguish the sounds /1/ and /r/, but then he/she is unable to do that. The baby is a fine instrument attuned to the sounds of his mother tongue because he/she needs them to communi­cate, to distinguish meaningful units. Sounds which are more frequent in all the languages are acquired first.

It takes us to the problem of input. The critical period for language acquisition is from birth to puberty during which time a child must be exposed to human speech communication. The term for a type of child-directed speech is motherese, or baby-talk: adults tend to talk to babies in a special way by exaggerating pitch changes, labialization and palatalization. It is not the only source of language because the child can also hear adult-to-adult talk. Generally, as was found in experiments, the child's

perception goes ahead of production: he/she can distinguish the sounds but fail to pronounce them properly.

It was found that the child is learning sounds to discriminate meaningful units, words and their grammatical forms. In English, for instance, the syntactic competence of a two-year-old child involves a patterned word order: subject — verb — object (SVO), while for a Russian child the morphology of words is more important, and the endings appear first, at the age of two.

Bilinguals are reported to create two vocabularies and two grammars simultaneously. They have an intermediate stage of cognate development when they can use the resource of one language for the other language usage. There are no generalizations about the phonetic discrimination of the two languages. Many bilinguals acquire the speaking fluency in both languages.

In second language learning there seems to be also the critical age after which the pronunciation of the target language is difficult to acquire. Every year counts and seems to diminish the chances of success. It should be noted, however, that unlike learning one's mother tongue, which in most cases is a creative but an unconscious process, second-language acquisition is both creative and conscious. A child or an adult is shown contrastive patterns of sounds, words and syntactical patterns, and a lot of things are explained. Motivation and practice are the necessary ingredients of success.

Just like imitation, analogy and reinforcement are not the only ways to learn the mother tongue, so are good models, drills and language environment not the only ways of learning a foreign language pronunciation. It takes a conscious effort to discriminate the automatic speaking habits of the mother tongue from those of the target language. Mastering them in mature age is quite a difficult task even for the persons placed in favourable language surroundings.