11) According to what theory may all consonants be of three types?

In linguistics, a consonant cluster (or consonant blend) is a group of consonants which have no intervening vowel. In English, for example, the groups /spl/ and /ts/ are consonant clusters in the word splits.Some linguists argue that the term can only be properly applied to those consonant clusters that occur within one syllable. Others contend that the concept is more useful when it includes consonant sequences across syllable boundaries. According to the former definition, the longest consonant clusters in the word extra would be /ks/ and /tr/,^[1] whereas the latter allows /kstr/. The German word Angstschweiß (/aŋstʃvaɪs/; "fear sweat") is another good example, with a cluster of five consonants: /ŋstʃv/. The Dutch word angstschreeuw (/ɑŋstsχrɪːw/; "scream of fear") has an even longer cluster, with six consonants: /ŋstsχr/. Consonants may be pronounced:  1. initially strong(and finally weak) - the beginning of a consonant may be more energetic, while the end may be weaker;  2. finally strong(and initially weak) - the beginning of the consonant may be weak, and its end more  energetic;  3. double– both the beginning and the end are energetic with a weakening of muscular tension in the middle, acoustically, they give the impression of two consonants. 

12) What is prof. N.I.Zhinkin’s theory about syllable division and syllable formation?

 Russian linguist and psychologist N.I. Zhinkin has suggested the so-called loudness theory which seems to combine both production and perception levels. The experiments carried out by N.I. Zhinkin showed that the arc of loudness of perception level is formed due to variations of the volume pharyngeal passage which is modified by contractions of its walls. The narrowing of the passage and the increase in muscular tension which results from it reinforce the actual loudness of a vowel thus forming the peak of the syllabic. So the syllable is the arc оf loudness which correlates with the arc of articulatory effort on the speed production level since variations in loudness are due to the work of all speech mechanisms.It is perfectly obvious that no phonetician has succeeded so far in giving an adequate explanation of what the syllable is. 

13. Which speech organ causes a syllable to be formed according to prof. N.I.Zhinkin?

Prof.N.I.Zhinkin's investigation of the mechanism of syllable formation and syllable division in the pronunciation of the Russian language may serve as a basis for a general theory of syllables. By using different complicated techniques Prof. B.I.Zhinkin found out which speech organ causes a syllable to be formed. This organ is the pharyngeal cavity. When the walls of the pharynx are contracted the passage through the pharyngeal cavity gets narrower. This process increases the actual loudness of the sound and the latter produces an "arc of loudness". Prof.N.I.Zhinkin's theory is often referred to as "loudness the¬ory”. Prof.N.I.Zhinkin has proved that the "arc of loudness" is due to the complex work of the speech mechanism as a whole (includ¬ing the work of the power, vibrator, resonator and obstructor mechanisms).