9.2 The Standard Model of Speech Production
Speech production falls into three broad areas: conceptualization, formulation and articulation (Levelt, 1989). In conceptualization, we determine what to say. This is sometimes known as message-level processing. Then we need to formulate the concepts into linguistic forms. Formulation takes conceptual entities as input and connects them with the relevant words associated with them to build a syntactic, morphological, and phonological structure. This structure is phonetically encoded and articulated, resulting in speech.
During conceptualization, we develop an intention and select relevant information from the internal (memory) or external (stimuli) environment to create an utterance. Very little is known about this level as it is pre-verbal. Levelt (1989) divided this stage into microplanning and macroplanning. Macroplanning is thought to be the elaboration of a communication goal into subgoals and connecting them with the relevant information. Microplanning assigns the correct shape to these pieces of information and deciding on the focus of the utterance.
Formulation is divided into lexicalization and syntactic planning. In lexicalization, we select the relevant word-forms and in syntactic planning we put these together into a sentence. In talking about word-forms, we need to consider the idea of lemmas. This is the basic abstract conceptual form which is the basis for other derivations. For example, break can be considered a lemma which is the basis for other forms such as break, breaks, broke, broken and breaking. Lemma retrieval used a conceptual structure to retrieve a lemma that makes syntactic properties available for encoding (Kempen & Hoenkamp, 1987). This can specify the parameters such as number, tense, and gender. During word-form encoding, the information connected to lemmas is used to access the morphemes and phonemes linked to the word. The reason these two processing levels, lemma retrieval and word-form encoding, are assumed to exist comes from speech errors where words exchange within the same syntactic categories. For example, nouns exchange with nouns and verbs with verbs from different phrases. Bierwisch (1970), Garrett (1975, 1980) and Nooteboom (1967) provide some examples:
- “… I left my briefcase in the cigar”
- “What we want to do is train its tongue to move the cat”
- “We completely forgot to add the list to the roof”
- “As you reap, Roger, so shall you sow”
We see here that not only are the exchange of words within syntactic categories, the function words associated with the exchanges appear to be added after the exchange (as in ‘its’ before ‘tongue’ and ‘the’ before ‘cat’). In contrast to entire words (which exchange across different phrases), segment exchanges usually occur within the same phrase and do not make any reference to syntactic categories. Garrett (1988) provides an example in “she is a real rack pat” instead of “she is a real pack rat.” In such errors, the seg