In most cases the morphemic structure of words is transparent enough and individual morphemes clearly stand out within the word. The segmentation of words is generally carried out according to the method of Immediate and Ultimate Constituents.
This method is based on the binary principle, i.e. each stage of the procedure involves two components the word immediately breaks into. At each stage these two components are referred to as the Immediate Constituents. Each Immediate Constituent at the next stage of analysis is in turn broken into smaller meaningful elements. The analysis is completed when we arrive at constituents incapable of further division, i.e. morphemes. These are referred to Ultimate Constituents. A synchronic morphological analysis is most effectively accomplished by the procedure known as the analysis into Immediate Constituents. ICs are the two meaningful parts forming a large linguistic unity. The method is based on the fact that a word characterized by morphological divisibility is involved in certain structural correlations. To sum up: as we break the word we obtain at any level only ICs one of which is the stem of the given word. All the time the analysis is based on the patterns characteristic of the English vocabulary. As a pattern showing the interdependence of all the constituents segregated at various stages, we obtain the following formula: un+ { [ (gent- + -le) + -man ] + -ly} Breaking a word into its Immediate Constituents we observe in each cut the structural order of the constituents.A diagram presenting the four cuts described looks as follows: 1. un- / gentlemanly2. un- / gentleman / - ly3. un- / gentle / - man / - ly4. un- / gentl / - e / - man / - ly A similar analysis on the word-formation level showing not only the morphemic constituents of the word but also the structural pattern on which it is built.The analysis of word-structure at the morphemic level must proceed to the stage of Ultimate Constituents. For example, the noun friendliness is first segmented into the ICs: [frendlı-] recurring in the adjectives friendly- looking and friendly and [-nıs] found in a countless number of nouns, such as unhappiness, blackness, sameness, etc. the IC [-nıs] is at the same time an UC of the word, as it cannot be broken into any smaller elements possessing both sound-form and meaning. Any further division of –ness would give individual speech-sounds which denote nothing by themselves. The IC [frendlı-] is next broken into the ICs [-lı] and [frend-] which are both UCs of the word. Morphemic analysis under the method of Ultimate Constituents may be carried out on the basis of two principles: the so-called root-principle and affix principle.
According to the affix principle the splitting of the word into its constituent morphemes is based on the identification of the affix within a set of words, e.g. the identification of the suffix –er leads to the segmentation of words singer, teacher, swimmer into the derivational morpheme – er and the roots teach-, sing-, drive-. According to the root-principle, the segmentation of the word is based on the identification of the root-morpheme in a word-cluster, for example the identification of the root-morpheme agree- in the words agreeable, agreement, disagree.
As a rule, the application of these principles is sufficient for the morphemic segmentation of words.However, the morphemic structure of words in a number of cases defies such analysis, as it is not always so transparent and simple as in the cases mentioned above. Sometimes not only the segmentation of words into morphemes, but the recognition of certain sound-clusters as morphemes become doubtful which naturally affects the classification of words. In words like retain, detain, contain or receive, deceive, conceive, perceive the sound-clusters [rı-], [dı-] seem to be singled quite easily, on the other hand, they undoubtedly have nothing in common with the phonetically identical prefixes re-, de- as found in words re-write, re-organize, de-organize, de-code. Moreover, neither the sound-cluster [rı-] or [dı-], nor the [-teın] or [-sı:v] possess any lexical or functional meaning of their own. Yet, these sound-clusters are felt as having a certain meaning because [rı-] distinguishes retain from detain and [-teın] distinguishes retain from receive. It follows that all these sound-clusters have a differential and a certain distributional meaning as their order arrangement point to the affixal status of re-, de-, con-, per- and makes one understand - tain and – ceive as roots.
The differential and distributional meanings seem to give sufficient ground to recognize these sound-clusters as morphemes, but as they lack lexical meaning of their own, they are set apart from all other types of morphemes and are known in linguistic literature as pseudo- morphemes. Pseudo- morphemes of the same kind are also encountered in words like rusty-fusty.