The following is an excerpt from my thesis, written in 2000.
Ambiguity is an inherent property of all natural languages, including English (Jespersen 1922; Williamson 1994). Absolute precision of a language is pragmatically undesirable, because the language is unable to adapt to new concepts (Williamson 1994). The communication needed to ensure effective and efficient report production, however, requires complete clarity. Hence, a tension exists between the natural language’s need for flexibility in the long term and the need for precision in the short term. Natural language is at once both dysfunctional and poorly adapted to the functions language needs to perform, yet flexible and broad-based such that it is useable in practice (Chomsky 1990).
Interest in linguistic ambiguity has an extensive history, and has been recognised as a separate branch of study since at least Aristotle’s time (Kooij 1971). Aristotle noted that language must be ambiguous, as a language has limited words but an infinite number of things and concepts to which those words must apply (Kooij 1971).
Russell (1923) recognised that all natural languages are vague and ambiguous. Excluding the realm of mathematical symbolism, constructing completely unambiguous expressions is not possible with the syntax and vocabulary tools available within natural languages (Williamson 1994). To endure and survive, language requires the flexibility to communicate new concepts. Ambiguity necessarily derives from the flexibility of natural language.
Kooij (1971) states that ambiguity arises where a sentence can be interpreted in more than one way. Similarly, Walton (1996) considers a sentence or statement to be more ambiguous as the number of legitimate interpretations of the sentence (or paragraph) increase. Ambiguity implies multiplicity of meaning (Walton 1996).
In classical analysis, the multiplex (Latin for "multiple meaning") categorisation of Alexander of Aphrodisius (Hamblin 1970) suggests a basis for the identification of categories of ambiguity. In classical literature, Alexander of Aphrodisius identified three categories of ambiguity: potential, actual, and imaginary. Walton (1996) adapts this classical multiplex categorisation to his identified types of ambiguity.
Walton (1996) identifies six classical types of ambiguity in natural language: lexical, syntactical, inflective, pragmatic, emphatic, and suggestive. In addition to Walton’s (1996) taxonomy, extraneous information and noise in the communication can also be a source of ambiguity. Extraneous ambiguity arises where the communication is not parsimonious, or the communication includes information that is not directly relevant to the message being communicated (Fowler and Aaron 1998). Extraneous ambiguity is an actual ambiguity within the Walton (1996) taxonomy.
Each ambiguity type can be independently present within the communication. Walton’s (1996) modified taxonomy and model of ambiguity is presented in Figure 1.
Types of Ambiguity (adapted from Walton 1996)