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), a pag.1

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

Morphemes may be composed of (1) segmental phonemes, (2) suprasegmental phonemes, and (3) combination of segmental and suprasegmental phonemes.
- Nida (1949), a 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), a 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), a pag.67

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

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