An OT Approach to Spanish and Thai Learners' Production of Past Tense Markers in L2 English

The present study investigates the production of the English past tense marker –ed by two qualitatively different groups of second language (L2) learners , namely, native speakers of Thai and Spanish. Several current models in L2 phonology are critically evaluated in order to explain variation in learners' production of functional morphemes. These models include the Organic Grammar Hypothesis (OGH), the Failed Functional Features Hypothesis (FFFH), the Prosodic Transfer Hypothesis (PTH), and the Phonological Reduction Hypothesis (PRH). The study argues that the Optimality Theoretic model provides a dynamic and predictive account of interlanguage variation. Before analyzing the variable productions of the learners, the phonological system of codas in Thai and Spanish is analyzed to determine the constraint rankings in the learners' L1s. The ranking of Thai is *COMPLEXCODA, *VOICED-CODA >>; DEP-IO >> MAX-IO; in the case of Spanish, *COMPLEXCODA]WORD, *[d]CODA >> DEP-IO >> MAX-IO. According to these constraint rankings, two predictions were proposed- (1) high-ranked markedness constraints in the L1 grammars of Thai and Spanish lead learners to make errors when producing verbs marked with –ed, and (2) the strategy of deleting the second element of consonant clusters is preferred to inserting a vowel in learners' productions. The results show that most learners successfully produced VV-d and CV-d verbs but encountered difficulties with complex clusters. Furthermore, the learners tended to choose the strategy of deletion over epenthesis in the structures of consonant clusters. The current findings suggest that constraint re-ranking in learners' interlanguage grammars accounts for the variable productions of the morphological marker –ed. This analysis supports the ability of OT to explain both accuracy and variation in L2 morphological production.