We discuss what factors influence the acquisition of morphophonemic alternations. What mechanisms are available to the learner; what is the basis for grammatical generalizations? Using the Artificial Language Paradigm we compared the acquisition of three alternations differing in phonetic substance, locality, and amount of exposure: one alternation was substantively based and structurally l ocal, another one was structurally local but not substantively based, and the last alternation was neither substantively based nor structurally local. Within each alternation we exposed the experimental groups to a greater or smaller number of instances. Results show a clear advantage for the substantively based alternation during acquisition. In addition, the local dependency has an advantage over the non-local one and alternations that are presented frequently have an advantage over those that are presented infrequently. We show that all three factors influence the acquisition of morphophonemic alternations, but they do so to a different d egree. Phonetic substance causes the strongest boost in the acquisition process and builds on locality, which also plays a role, and amount of exposure influences the acquisition process independent of the nature of the alternation. We argue that acquisition models should take the interaction of these factors into account.

Recent research has shown that seemingly identical suffixes such as word-final /s/ in English show systematic differences in their phonetic realisations. Most recently, durational differences between different types of /s/ have been found to also hold for pseudowords: the duration of /s/ is longest in non-morphemic contexts, shorter with suffixes, and shortest in clitics. At the theoretical level such systematic differences are unexpected and unaccounted for in current theories of speech production. Following a recent approach, we implemented a linear discriminative learning network trained on real word data in order to predict the duration of word-final non-morphemic and plural /s/ in pseudowords using production data by a previous production study. It is demonstrated that the duration of word-final /s/ in pseudowords can be predicted by LDL networks trained on real word data. That is, duration of word-final /s/ in pseudowords can be predicted based on their relations to the lexicon.

2012) Sentence comprehension in competing speech: Dichotic sentence-word priming reveals hemispheric differences in auditory semantic processing, Language and Cognitive

Using the artificial language paradigm, we studied the acquisition of morphophonemic alternations with exceptions by 160 German adult learners. We tested the acquisition of two types of alternations in two regularity conditions while additionally varying length of training. In the first alternation, a vowel harmony, backness of the stem vowel determines backness of the suffix. This process is grounded in substance (phonetic motivation), and this universal phonetic factor bolsters learning a generalization. In the second alternation, tenseness of the stem vowel determines backness of the suffix vowel. This process is not based in substance, but it reflects a phonotactic property of German and our participants benefit from this language-specific factor. We found that learners use both cues, while substantive bias surfaces mainly in the most unstable situation. We show that language-specific and universal factors interact in learning.