Linguistics: Morphology

Morphology, the study of the internal structure of words, reveals many properties that make sign languages unique.

Words or signs can be decomposed into one or more basic elements. Such elements are called morphemes. A morpheme is the smallest meaningful unit within a sign. In English, the word student consists of one morpheme, but the word teacher consists of two morphemes: ‘teach’ and ‘-er’. The American Sign Language (ASL) signs in (1a) consist of one morpheme, while those in (1b) contain two morphemes.

As we see in (1a), a morpheme encodes a consistent correspondence between form and meaning. For example, drive means an activity (i.e., ‘drive’). There is no way to divide the sign into two smaller units that have different meanings. Thus, the sign constitutes the smallest meaningful unit itself and consists of one morpheme. Turning to (1b), drive+er can be divided into two units, drive and -er. drive is one smallest meaningful unit, and -er is another smallest meaningful unit. -er has its own meaning (i.e. a person who does the activity), and it cannot be split into smaller meaningful units. For these reasons, drive and -er constitute two morphemes that are combined into a single sign.

By way of contrast, groups of signs, called lexical families, share the same specification for one or two phonological parameters and fall into the same semantic category. For example, the following signs in German Sign Language (DGS) share the same location, namely, the forehead. This location is consistently associated with the meaning “mental state.” However, the other phonological parameters (handshape and movement) are not associated with any meaning, since they do not appear in other contrasting signs. They [Page 614]merely function to distinguish signs from one another in a lexical family. Thus, the signs constitute one morpheme, not two.

Lexical families are comparable to phones-themes in spoken languages, which are clusters of words beginning with the same string of letters and having a related meaning. For example, English words starting with gl- tend to have meanings that have to do with sight: glance, glare, and gleam. However, they cannot be treated as consisting of two morphemes, because such strings of letters appear in other words with unrelated meanings. For example, the following English words begin with gl- but have nothing to do with sight: glacier, glad, and gland. Moreover, the strings of letters do not attach to any obvious morpheme (e.g., in glance, gl- attaches to -ance, but -ance does not have any meaning of its own).

Morphemes can be bound or free. A bound morpheme cannot stand on its own in an utterance, for example, -er in English and -er in ASL. In contrast, a free morpheme can stand on its own in a sentence (e.g., teach in English and drive in ASL). In another sign language, like DGS, there is a form glossed as person that is similar in meaning to the -er morpheme in ASL. This is not a bound morpheme but rather a free morpheme.

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