Theoretical Approaches to Speech Production :: Spreading Activation Theory SAT

Theoretical Approaches to Speech ProductionThere are two main theories of Speech production, diffusion Activation Theory - SAT ( dingle, 1986 Dell & OSeaghdha, 1991) and Word- Form Encoding by Activation and Verification WEAVER++ (Levelt et al., 1989 1999).The SAT theory was devised by Dell (1986) then revised by Dell & OSeaghda (1991). The theory works on a 4 aim connectionist assume par each(prenominal)el and dynamic.The Semantic level is the meaning of what is going to be said.The Syntactic level is the grammatical structure of the raillerys in the planned utteranceThe Morphological level is the morphemes ( underlying units of meaning of word forms) in the planned sentence.The Phonological level is the basic unit of sound within a sentence. In addition to the main structure of the SAT model a representation is formed at each level. Pre-Planning is more particular at the semantic level. There are categorical rules at each level, which get down constraints on item categories a nd category combination.The internal lexicon (dictionary) is considered to be a constructionist network it includes nodes for concepts, words, morphemes and phonemes. So when one node is activated it sends a message to activate all other nodes connected to it.The later computational model WEAVER++ was put forward by Levelt, Roelofs, and Meeyer (1999) derived from Lefvelt (1989).The model is based on the assumptions that there is a fertilize forward activation network spreading through the network and does not go back. There are 3 levels in the network the highest level of nodes equal are lexical the second level are lemmas which are abstract words from the mental lexicon and the lowest level are the nodes in support of morphemes the basic unit of meaning and phonemes. The network does not have any inhibitory links. The production of speech follows through the stages exactly serial. A word error leave behind occur if the level of activity in the node does no match to the appropria te node higher up. There are 6 stages of processing in the WEAVER++ Theory 2 more than the SAT theory. First the Conceptual preparation stage where the lexical concepts are activated. Stage 2 comes the Lexical pick where an abstract word or lemma is Selected along with its syntactic features. The Morphological encoding is The basic word form derived from the lemma activated. Stage 5 is the phonic encoding is where the speech sounds are set. Articulation is the Final stage defines the way the word is pronounced.