Rule I. Syllabic indivisibility. If we compare the following words: butcher [‘bυt∫-ə] – lightship [‘lat-∫p]
mattress [‘mætr-s] – footrest [‘fυt-rest]
curtsey [‘k3:-ts] – out-set [‘aυt-set]
eighth [etθ] – whitethorn [‘wat-θo:n]
we could see that in the words given in the left column the sounds [t∫], [tr], [ts], [tθ] belong to one syllable and cannot be divided into two elements by a syllable-dividing line. We could compare these complexes to the Russian [ц] phoneme which also cannot belong to different syllables. Cf. [иай-‘цо], но [cъ-вет-ский]. We could assume that the articulation of the voiced counterparts does not differ from the voiceless ones.
Rule II. Articulatory indivisibility. We might say that special instrumental analysis shows that all the sound complexes in question are homogeneous and have the maximum of articulatory features in common; that is at the beginning of the articulation the organs of speech are in the position of the second fricative element [∫], [r], [s], [θ] or [3], [z], but there is a complete obstruction (a closure) formed by the tip and the sides of the tongue against the alveolar ridge and the side teeth. Then the closure is released and the air escapes from the mouth cavity, producing audible friction. In other words the above-mentioned complexes are produced by one articulatory effort.
Rule III. Duration. We should note here that the available data of that kind is not reliable enough. Moreover [t∫, d3] complexes which are considered phonemes by all phoneticians, are not defined properly as to their length or quantity. With G.P.Torsuev, we could state that length of sounds depends on the position in the phonetic context, therefore it cannot serve a reliable basis in phonological analysis. He writes that the length of English [t∫] in the words [t∫εə] chair and [mæt∫] match is different, [t∫] in match is considerably longer than [t] in mat and may be even longer than [∫] in mash. This does not prove, however, that [t∫] is biphonemic.
N.S.Trubetskoy himself admits that this condition is less important than the two previous ones.
From what we have said it follows that this rule has no decisive value. That is why we could be certain that the analysed sounds are articulatively indivisible. So potentially they can be considered monophonemic. But in fact they could be considered monophonemic on condition they could enter the "phonological model of the language".
The rules suggested by N.S.Trubetskoy are based on articulatory and phonological indicators. They may well be called the grounds of phonology, because in great many instances they permit us to define the phonemic status of sound complexes. However, doing credit to articulatory and phonological criteria applied in the interpretation of such entities, scholars seem to attach decisive importance to morphonological criterion: According to this criterion a sound complex is considered to be monophonemic if a morpheme boundary cannot pass within it, because it is generally assumed that a phoneme is morphologically indivisible. If we consider [t∫], [d3] from this point of view we could be secure to grant them a monophonemic status, since they are indispensable. As to [ts], [dz] and [tθ], [dθ] complexes their last elements are separate morphemes [s], [z], [θ], so these elements are easily singled out by the native speaker in any kind of phonetic context. So these complexes do not correspond to the phonological models of the English language and cannot exist in the system of phonemes. The case with [trj, [dr] complexes is still more difficult. According to morphonological criterion they have more grounds than the above-mentioned [ts], [dz], [tθ] and [dθ] to be considered monophonemic because they very often belong to the same morpheme. In such situations analysts apply the native speaker's knowledge, which might serve an additional criterion, for any linguistic analysis can be largely based on intuition about the rules to be recognized, combinations to be noted and results to be obtained. So talking about [t∫], [d3], if we assume that in the word chair [t] is dispensable leaving share [∫εə] and [∫] is dispensable leaving tear [tεə] and therefore it is a sequence of [t] + [∫], the native speaker's feeling cannot accept it as anything but a unit. Perhaps the reason is partly to do with [d3] which cannot be treated so easily as [t∫]. If we dispense [d] in [d3e], for example, we could get [3e], but [3] is not a permitted initial phoneme in English because it occurs only in a few borrowed words. So it is not satisfactory, because it would be odd to treat one of the correlated pairs as a sequence, and the other as a unit. Another reason: if we treat [t∫], [d3] as sequences what other sequences of this type would we find in the system of English consonants? Parallel to the [dr] complex there are [kr], [pr], [θr]. But there is nothing parallel to [t∫] and similarly to [d3]. So it may be said that the native speaker does not regard [t∫], [d3] as composite sounds, that is composed of distinctive elements. On the other hand, [tr], [dr] are not normally regarded as anything but sequences. A.C.Gimson himself admits that he grants them monophonemic status on the basis of the articulatory criterion.
By way of conclusion we could say that the two approaches that have been adopted towards this phenomenon are as follows: the finding that there are eight affricates in English [t∫], [d3], [tr], [dr], [ts], [dz], [tθ], [dθ] is consistent with an articulatory and acoustic view, because in this respect the entities are indivisible. This is the way the British phoneticians see the situation. This point of view underestimates the phonological aspect and is in a way an extremity.
On the other hand, Soviet phoneticians are consistent in looking at the phenomenon from the morphological and the phonological point of view which allows them to categorize [y], [d3] as monophonemic units and [tr], [dr], [ts], [dz], [tθ], [dθ] as biphonemic complexes. However, this point of view reveals the possibility of ignoring the articulatory and acoustic indivisibility of the complexes. In this case the pronunciation peculiarities of these complexes are not analysed properly. It must be distinctly understood that that is a genuine articulatory difference between phonemes [t], [d] pronounced in combination with other sounds and the [t], [d] as parts of clusters [tr], [dr]. It requires special attention and training. On this account textbooks in practical phonetics should include effective instructions on teaching the pronunciation of these sound complexes.
So far we have attempted to show how a fairly general problem of interpreting the system of English consonants is solved, what essential complication exists and what kind of criteria can be used in solving these problems.
Summarizing what have been described we could state that with the majority of Soviet specialists in English phonetics we consider relevant the following articulatory features:
1) type of obstruction,
2) place of obstruction and the active organ of speech,
3) force of articulation.
As was mentioned in the previous section, the phonetic, system of a language is patterned. So we have tried to show what articulatory features could serve as a criterion for grouping consonants into functionally similar classes. The above-mentioned articulatory characteristics are undoubtedly the prime ones as they specify the essential quality of a consonant which is enough to describe it as an item of a system. On this level of analysis it is the point where the distinction between consonants becomes phonemic that matters. However, if we approach the matter from "teaching pronunciation" point of view it is natural we should want to gain some additional information about the articulation of a consonant, about such delicate distinctions that make the description complete from the articulatory point of view, for example, if the consonant is apical or dorsal; if it is dental, alveolar, post-alveolar, or palato-alveolar; if it is oral or nasal; if the narrowing is flat or round and a lot of others. These characteristics are of no importance from phonological point of view but they provide necessary and instructive information for comparison between the English consonants and those of the mother tongue and so are considerably important for teaching purposes. It is for this reason that these characteristics are normally included into the classification.