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OF VOWEL AND CONSONANT PHONEMES

ARTICULATORY TRANSITIONS

LECTURE 6

Контрольні запитання

Відповідність між різними адресами

Символьні адреси

Числові адреси є зручними для адміністрування, але для користувачів така адресація є незручною, тому для мереж різного масштабу існують символьні імена, які однозначно ідентифікують комп’ютер чи групу вузлів і зазвичай, мають змістовні назви – admin, student, decanat, site.ua.

Відповідністю між адресами різних типів займається служба розподілу адрес, яка може бути централізованою або розподіленою.

Для централізованого підходу в мережі виділяється один комп’ютер – сервер імен, в якому зберігається таблиця відповідності адрес різних типів (МАС, ІР, символьних). Решта комп’ютерів мережі звертаються до нього.

При розподіленому підході, кожний комп’ютер сам вирішує цю задачу. Перед початком передачі він відправляє до всіх вузлів широкомовне повідомлення, щоб відгукнувся власне вузол з заданою числовою адресою або символьним іменем. Запит отримують всі вузли, порівнюють вказану адресу зі своєю. Відгукується той вузол, де збіглася адреса і до нього скеровується повідомлення.

При розподіленому підході не потрібно виділяти сервер імен і задавати таблицю відповідності, але такі широкомовні повідомлення перевантажують мережу.

Централізований підхід застосовують у великих мережах, а розподілений – у невеликих.

1. Які вимоги висуваються до адресації вузлів та схеми її призначення?

2. Які функції покладено на широкомовні адреси?

3. Яка адреса є основною для отримання послуг локальної мережі?

4. Що позначає ІР-адреса комп’ютера?

5. Як розподіляються адреси за системою класів ІР-адрес?

6. Скільки байтів відведено для позначення номера мережі класу С?

7. Для чого введено автономні ІР-адреси?

8. Які дії покладено на ІР-адресу, перший октет якої є 127?

9. Як встановлюється відповідність між адресами різних типів?

10. Які функції покладено на сервер імен в локальних мережах?

 

 

In the process of speech, i.e. in the process of transition from the articulatory work of one sound to the articulatory work of the neighbouring one, sounds are modified. The adaptation of the articulatory work of the two neighbouring sounds may result in assimilation. Assimilation may be not only contact, but also distant when distant sounds are affected. On the phonological level the sounds modified in the process of assimilation are analysed as positional variants of vowel and consonant phonemes.

Assimilation which occurs in everyday speech nowadays is called living, assimilation the results of which can be traced on the diachronic level is called historical. For example, the words permission and measure were pronounced as /par'misjan/, /'mezjur/. In the course of time /sj/, /zj'/ turned into /∫/ and /z*/.

Present day assimilation can be subdivided into partial and complete.

Complete assimilation is characterized by complete similarity of the two sounds, e.g. cupboard /'kAb∂d/, in this word the sound /p/ is completely assimilated to /b/.

Partial assimilation is characterized by partial similarity of one sound to the other. It can be subdivided into:

a) progressive,

b) regressive,

c) reciprocal [-`sip-].

Assimilation is progressive when the first of the two sounds affected by assimilation makes the second sound similar to itself, e.g. desks, pens, the sounds /k/ and /n/ make the plural inflection /s/ similar to themselves: voiceless in /desks/ and voiced in /penz/.

Assimilation is regressive when the assimilated sound precedes the conditioning sound, for example, in the combination in the /n/ becomes dental assimilated to the next interdental /ð/. Assimilation is reciprocal when both sounds are equally affected by assimilation, e. g. twice, /t/ is rounded under the influence of /w/ and the latter in its turn becomes partly devoiced under the influence of voiceless /t/.

To make the mechanism of articulatory transitions clear it should be viewed in detail in terms of the articulatory work of the speech producing mechanisms.

Each sound pronounced in isolation has three stages in its articulation.

During the first stage the organs of speech move to the position which is necessary to pronounce the sound. It is called differently by different authors: initial, on-glide, excursion.

During the second stage the organs of speech are kept for some time in the position necessary to pronounce the sound. This stage is called: medial, stop-stage, retention stage, the hold.

During the third stage the organs of speech move away to the neutral position. This stage is called final, off-glide, recursion, release.

There are two ways of joining the sounds:

(1) merging of stages – when the final stage of the first sound merges with the initial stage of the second sound, and

(2) interpenetration of stages – when the medial stage of the second sound "penetrates" into the medial stage of the first sound.

Merging of stages usually takes place when sounds of different nature are joined together: vowels and consonants, for instance.

In the word law the two sounds /l/ and /э:/ are joined by way of merging their stages.

The first stage for /l/ is the raising of the front edge of the tongue to the alveolar ridge and simultaneous lifting of the middle part of the tongue to the hard palate (the soft palate is raised). As soon as the tip of the tongue touches the teeth ridge and the sides of the tongue are lowered forming lateral passages, the vocal cords are brought together and made tense, the air passing between the vocal cords makes them vibrate; the vibrating air fills the pharynx, the mouth cavity and escapes through the lateral passages producing a clear allophone [l] of the /l/ phoneme – it is the medial stage of the lateral sonorant /l/. After that the final stage begins; the tongue is separated from the teeth ridge and lowered together with the lower jaw, at this very moment – when the tongue takes up the back low narrow position and the lips begin to get rounded for the /э:/ articulation – the first, or initial, stage of /э:/ takes place. When the bulk of the tongue is kept for some time in the position mentioned above, with the lips slightly rounded, the air passes through the pharynx and the mouth cavity, acquiring the quality of the English /э:/ – the second, or medial, stage for /э:/ begins. When the hold of the monophthong /э:/ is over, the vibration of the vocal cords stops – the final stage is accomplished.

Interpenetration of stages takes place when sounds of a similar or identical nature are joined together.

For example, in the word bottle the sounds /t/ and /l/ are joined interpenetrating their stages. It happens in the following way: at the moment of the hold of /t/, i.e. during its medial stage, when the tip of the tongue is pressed against the teeth ridge, the sides of the tongue are lowered, letting the air pass through these narrow air passages (or one passage, if one side of the tongue is lowered), the lateral plosion is the second, medial stage of the /l/ articulation. At this moment the vocal cords vibrate and the air passes through the pharynx and the mouth cavity along the lateral passages, producing the dark allophone [ł] of the /l/ phoneme.

After the hold of /l/ is accomplished, the final stage of /l/ begins, that is the tongue returns to the neutral position and the vocal cords stop to vibrate.

The articulatory peculiarity of the /t/ to /l/ transition results in the loss of plosion in the /t/ production.

This way of the /t/ to /l/ transition is called lateral plosion.

If the medial stage of the first sound coincides with the initial stage of the second sound, this type of articulatory transition is called close, if the final stage of the first sound is followed by the initial stage of the second sound this transition is called loose.

PECULIARITIES OF THE CC, CV, VC, VV ARTICULATORY TRANSITIONS IN ENGLISH AND IN UKRAINIAN

(1) Aspiration

One of the features which are peculiar to CV transition in English is aspiration. This phenomenon does not exist in Ukrainian. In English it is observed in the pronunciation of the initial p, t, k followed by an accented vowel. If p, t, k are preceded by s, there is no aspiration.

Aspiration may be defined as a “voiceless interval consisting of strongly expelled breath between the release of the plosive and the onset of the following vowel”. It is phonemically relevant in pairs try – dry, crate – great etc. because these pairs are distinguished by the presence of aspiration rather than through the presence of voice. Some phoneticians mark aspiration by a raised h. Aspiration is stronger if p, t, k are followed by a long vowel, compare Pete, pit.


Читайте також:

  1. Accommodation of OE Vowels (breaking and diphthongisation).
  2. Differentiating consonants with same location and manner of articulation
  3. Independent Vowel Changes in Proto-Germanic
  4. The system of consonant phonemes. Problem of affricates
  5. Vowel Gradation with Special Reference to Verbs




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