Morphemes are the minimal meaningful units which may constitute words or parts of words, e.g. 're-', 'de-', 'un-', '-isch', '-ly', '-ceive', '-mand', 'tie', 'boy', and 'like' in the combination 'receive', 'demand', 'untie', 'boyisch', 'likely'.
- Nida (1949), Pag. 1

The recurring meaningful parts of utterances are morphemes.
- Nida (1949), Pag. 10

Morphemes may be composed of (1) segmental phonemes, (2) suprasegmental phonemes, and (3) combination of segmental and suprasegmental phonemes.
- Nida (1949), Pag. 62

Theoretically, there is no restriction on the shape and size of morphemes. For example, in English there are morphemes such as 'goulash' and 'talmud' and ones as '-s' in 'lips' and '-d' in 'told'.
- Nida (1949), Pag. 65

The parts of morphemes usually occur in continuous sequence if all of them are segmental; they are superimposed if they include segmental and suprasegmantal phoneme. [...] Sometimes, however, parts of morphemes consisting of segmental phonemes do not occur in continuous sequence.
- Nida (1949), Pag. 67

Morphemes have the following positional types of occurrence: (1) successive, (2) included, and (3) simultaneous.
- Nida (1949), Pag. 76

No morphemes or combination of morphemes are identical in meaning.
- Nida (1949), Pag. 151