In most languages only some of the combinations of phonemes constitute morphemes, and in all languages a morphological analysis […] is required to tell which these are.
- Harris (1951), a pag.24

[…] when we identify the morphemes, we may find that some of those having two phonemic forms could be reduced to one phonemic form by reassigning their segments to other phonemes. For instance, if we had assigned the [t] which occurs in /s- —/ to /d/ we would have /disdeyst/ for 'distaste' and /teyst/ for 'taste'. We can give one phonemic form to both these occurrences of the morpheme taste by reassigning the [t] of /s—/ to /t/. having done this, we must go back and change the phonemic composition of all morphemes which contained the [t] segments: we had written 'stay' /sday/, but must now change it to /stey/.
- Harris (1951), a pag.77

When written componentally […] the morpheme does not have different alternants, and a morphophonemic statement is thus avoided. An example of this is seen in fn. 13 above, where the basis for identical componental writings is the fact that a component of one morpheme is so defined as to extend over another morpheme which itself does not contain the component.
- Harris (1951), a pag.134, n.20

In many languages it will not prove convenient, from the point of view of economy of statement, to consider every independent sequence a morpheme, as in the case of the /g/ of 'bag'. For if we sought to state the relations between such morphemes, we would find few, if any, broad generalizations.
- Harris (1951), a pag.160

The term morpheme will sometimes be used for either morphemic segment or the full morphemes […] if the difference between them is irrelevant in the context, or if it is entirely clear from the context which of the two is meant.
- Harris (1951), a pag.165, n.16

An intrinsic part of the definition of each morpheme is the environment for which it is defined: /siyliŋ/ by itself is undefined as to consisting of one morpheme ('ceiling') or two ('sealing'). But in 'We are going —.' /siyliŋ/ is defined as consisting of two morphemes, while in 'That — is made of plaster.' /siyliŋ/ is defined as one morpheme.
- Harris (1951), a pag.171

[…] the morphemes are those phonemically identifiable elements in terms of which the interelement relations can be most simply stated. However, in any description of a particular language, the morphemes are defined by a list of individual morphemes.
- Harris (1951), a pag.171, n.34

Often we will find that some morphemes have juncture phonemes at their boundaries, while others do not: e.g. English morphemes ending in /ay/ are marked with juncture since /ay-/ represents the segments [a :y] whereas /ay/ is [a.y] or [ay] depending on the following consonant: /slay-nƏs/ for [sla:ynƏs] 'slyness'; /maynƏs/ for [maּynƏs] 'minus'.
- Harris (1951), a pag.175, n.45

It might be most convenient to define morphemes as phonemically identifiable elements in particular positions relative to particular other such elements. Elements in different positions need not be identified as the same element, just as homonymous elements in different environments need not be. Thus, we have Bengali verb plus 'na' for negative of a verb, but 'na' plus verb for the negative in a subordinate clause (even when there is no subordinate particle).
- Harris (1951), a pag.185, n.61

[…] in general morphemes which differ in meaning will also differ in their environments, if we take sufficiently long environments and enough of them.
- Harris (1951), a pag.189, n.67

Some morphemes, frequently including the morphemic element of order […] have so-called grammatical meanings, e.g. the Kota echo-word 'gıX' which means ‘and other things like what is referred to in the preceding morpheme’.
- Harris (1951), a pag.192

Since the morphemes are sequences of phonemes, they represent features or portions of the flow of speech.
- Harris (1951), a pag.195

Morphemes cannot therefore be derived from phonemes merely by application of logical operations such as were used in 7-10. We can determine the morphemes (or the points of morpheme boundary) in a language only by utilizing additional information, such as that indicated in 12 [Morphological elements: morphemic segments]. Even in languages where all morphemes are of the same length, so that every so many phonemes constitute a morpheme (in Annamese: every sequence of consonant plus vowel plus tone), the morpheme is not entirely derivable from the phonemes: for whence did we know in the first place that all morphemes in this language are of the same length, and that that length is so and so many phonemes?.
- Harris (1951), a pag.196

In many languages almost no two morphemes occur in a completely identical range of environments. E.g. 'hotel' and 'tavern' would occur in 'I’m staying at the —', but 'rug' would hardly occur there.
- Harris (1951), a pag.201, n.10

In some morphemes there are many members all of which have certain similarities and differences in common. In the Attic Greek reduplication morpheme, the members consist of some one consonant (whichever follows the morpheme) plus /e/. In the French suffix morpheme for ‘male’ the members consist of dropping some one consonant (whichever precedes the morpheme).
- Harris (1951), a pag.211

In some morphemes there is no phonemic resemblance among the members. Thus /gud/ are members of the same morpheme {'good'}, the second form (in 'better') occurring only before the morpheme {'er'}.
- Harris (1951), a pag.211

The term morpheme is often used particularly for groups of complementary segments (not contours or order) […] which are quite similar to each other in phonemic composition […].
- Harris (1951), a pag.213, n.31

From the fact that each morpheme is a class of one or more complementary or freely varying morphemic segments, it follows that only two facts are essential for each morpheme: what its segment members are (each being identified by its phonemic composition); and in what environments each member occurs. It was seen in 13.53 that morphemes also differ in the phonemic similarity between each member and its environment. Some of those alternations, both in phonemic composition and in environmental differentiation, among members of a morpheme occur in only one morpheme; others occur identically in many morphemes.
- Harris (1951), a pag.219

In some cases a number of morphemes have analogous phonemic alternations among their members in corresponding environments, with such limitations that either the morphemes or the differentiating environments have to be identified morphemically: i.e. either the morphemes in which the alternation occurs cannot be distinguished by a common phonemic feature that is absent from all the morphemes in which the alternation does not occur […]; or else the environments of one alternant do not have a common phonemic feature that is absent from all the environments of the other alternant ([…] the environment of the alternant '–ren' is not differentiable phonemically from the environments of the alternants /s/, /z/ which contain among them the family name 'Childe: We had dinner with the children. We had dinner with the Childes.').
- Harris (1951), a pag.220

In some cases all the morphemes which have some particular phonemic form in common have also an analogous alternation of members in the neighborhood of a particular morpheme. E.g. all morphemes which have members ending in /k/ when not before 'ity', have members ending in /s/ instead when before 'ity': 'opaque-opacity'; {'ic'} in 'electric-electricity'. In such cases, it is possible to say that all morphemes which occur before ity will in that position have members differing in certain phonemes from the other members of the respective morpheme: in particular, if the other member (the one not before 'ity') ends in /k/, the member before 'ity' ends in /s/; if the other member contains /eyC/ or /ayC/, the member before 'ity' contains /æC/ or /iC/ respectively ('sane-sanity'); and so on.
- Harris (1951), a pag.221

[…] in some cases all the morphemes which had some particular phonemic feature have analogous phonemic alternation among members in the neighborhood of all other morphemes which have some particular phonemic feature. In Kota, all morphemes which, when they do not occur before a morpheme beginning with /k/, have members ending in /ky/, have otherwise identical members without the /ky/ when they occur before a morpheme beginning with /k/: /aky/ ‘husked grain’, /kayḷ/ ‘female stealer’, /aki.ḷ/ ‘female stealer of husked grain’. The same alternation occurs for /t/ and /n/: /katač/ ‘knife and stick’, but /katy/ ‘knife’ and /tač/ ‘stick’; /kuṇo ṭḷk/ ‘to look for bees’, but /kuṇy/ and /ṇo ṭḷk/ separately.
- Harris (1951), a pag.222

The ideal is that every morpheme have only one phonological constitution (spelling), different from that of every other morpheme. This ideal was in part made unattainable by the operation of 13.31, which assigns a phonemic sequence in some environments to one morpheme and in other distributions to another morpheme. It was made farther removed by the operations of 13.32 (and 13.2), which included phonemically distinct morphemic segments in one morpheme. The operation of 14.3 recaptures some of the lost ground (on a different level) by enabling us to say that morphemes are morphophonemically, if not phonemically, identical in all their occurrences. In 14.5-6, we then check back to see if a redefinition of some of our phonemes or morphemes would enable us to make this morphophonemic identity into a phonemic one.
- Harris (1951), a pag.237, n.41

[…] we frequently find morphemes whose distribution are partially identical: in some environments all of these morphemes occur, but in other environments only particular ones of these morphemes are to be found.
- Harris (1951), a pag.243

It will often be found that few morphemes occur in precisely all the environments in which some other morphemes occur, and in no other environments.
- Harris (1951), a pag.244

If a morpheme is a member of a particular class, which may be included in a particular general class, it is not a member of any other class.
- Harris (1951), a pag.257

Phonemically identical morphemes in one class are one morpheme […] no matter how different their meanings […]. Phonemically identical morphemes in different classes may be distinguished on the grounds of their different environments (e.g. /siy/ 'V' and /siy/ 'N' in 'I see, the sea'). If the classes of the two phonemically identical morphemes have some enviroments in common, utterances may occur in which we cannot distinguish which morpheme (or class) is present: in dialects where 'I can tell my horse is running.' and 'I can tell my horse’s running.' are homonymous, the hearer will not know from the utterance alone (if there are no differentiating neighboring utterances) which is meant. Similarly, we can distinguish rumour in 'It is — ed that we’ll be leaving soon.' from 'room + er I Did the — pay his bill?' But we cannot distinguish the two in 'That’s just a —'.
- Harris (1951), a pag.258

[…] all morphemes, in no matter what class, which are phonemically identical are ‘the same’ morpheme. The various /tuw/ morphemes, 'two', 'to', and 'too', would then be one morpheme occurring in various classes, as would the book in 'N' and 'V'. Alternatively we may wish to call book one morpheme, but /tuw/ three different ones. We might decide to consider phonemically identical morphemes in various classes as constituting a single morpheme only if a sufficiently large fraction of the morphemes of these various classes are phonemically identical, i.e. only if there is a sufficiently large number (in any case not just one) of such sets of phonemically identical morphemes distributed in precisely these classes: for 'N' and 'V' we have 'book', 'walk', and many others; for the full range of classes in which /tuw/ occurs we have no other case.
- Harris (1951), a pag.258, n.29

[…] we can regard the morpheme as a class of members, all equally limited to particular positions. However, in selecting a member of the us, 'ō' class to be considered part of 'hort-', we cannot avoid deciding for one member as against the others. We can select that member which occurs in the most general environments. E.g. if 'ō' occurs only in the neighborood of certain morphemes, and 'um' in the neighborhood of others, while us occurs in a great variety of environments, it is clearly convenient to select us as the member to be included with 'hort-'.
- Harris (1951), a pag.307, n.14

In most languages many morphemes will remain without being reduced to combinations of components; this will include morphemes and sub-classes which have unique limitations of occurrence of a type that does not lend itself to component representation […].
- Harris (1951), a pag.309

It frequently happens that a morpheme has unique restrictions upon its occurrence relative to certain other morphemes, and would thus properly constitute a class, or sub-class, by itself.
- Harris (1951), a pag.312

We may say therefore that each morpheme is composed directly of a sequence of morphophonemes, each of which in turn is a class consisting of one or more complementary phonemes or components. Each morpheme has only one morphophonemic constituency but the distinctions between sounds are in general only in one-many correspondence with the distinction between morphophonemes: two distinct morphophonemic sequences may represent identical segment (or phoneme) sequences; such different morphophonemic sequences are phonemically equivalent. It may be noted here that the morphemes are not distinguished directly on the basis of their meanings or meaning differences, but by the result of distributional operations upon the data of linguistics (this data including the meaning-like distinction between utterances which are not repetitions of each other). In this sense, the morphemes may be regarded either as expressions of the limitations of distribution of phonemes, or (what ultimately amounts to the same thing) as elements selected in such a way that when utterances are described in terms of them, many utterances are seen to have similar structure. The morphemes are grouped into morpheme classes, or classes of morphemes-in-environments, such that the distribution of one member of a class is similar to the distribution of any other member of that class […].
- Harris (1951), a pag.362

In some cases it is most convenient, in terms of the present methods, to consider the morpheme in question as a specially restricted member of the recognized morpheme class (within whose range of distribution its own distribution falls). This was done for the 'boysen' of 'boysenberry' […]. We assign 'boysen' to the class 'Nь' ('straw', 'goose', etc.) which occurs before '— berry'. The uniqueness of 'boysen' appears in the fact that most of the other members of 'Nь' occur also in other 'N' positions while 'boysen' does not. (p.312)
- Harris (1951), a pag.312