Human Behavior and Machine Simulation in the Processing of (Mor)Phonotactics – BE-SyMPHONic

Language sounds are realized in several different ways. Every language exploits no more than a sub-set of the sounds that the vocal tract can produce, as well as a reduced number of their possible combinations. The restrictions and the phonemic combinations allowed in the language define a branch of phonology so-called phonotactics.
Phonotactics refers to the sequential arrangement of phonemic segments in morphemes, syllables, and words (Harris 1955) and underlies a wide range of phonological issues, from acceptability judgments (pseudowords like <poiture> in French or <Traus> in German are phonotactically plausible) to syllable processes (the syllabic structure in a given language is based on the phonotactic permission in that language) and the nature and length of possible consonant clusters (that may be seen as intrinsically marked structures with respect to the basic CV template).

Exploring the psycho-computational representation of the phonotactics in French and German is the aim of this research project.

In particular, our research will focus on the interplay between phonotactics and word structure in French and German, and investigate in particular the behavioural and computational representations of phonotactic vs. morphonotactic clusters.

As a matter of fact, the basic hypothesis underlying this research project is that there exist different cognitive and computational representations for the same consonant cluster according to its phonotactic setting. In particular, the occurrence of a cluster across a morpheme boundary (morphonotactic cluster) is considered as particularly interesting, for the following reasons.
Our research will focus on the interplay between phonotactics and morphology and investigate the behavioural and computational representations of consonant clusters according to whether they are: a) exclusively phonotactic clusters, i.e. the consonant cluster occurs only without morpheme boundaries (e.g. Stein in German); b) exclusively morphonotactic clusters, i.e. the consonant cluster occurs only beyond morpheme boundaries (e.g. lach+st), c) both are true with one of the two being more or less dominant (e.g. dominant lob+st vs. Obst)1.

Thus we test the existence of different ‘cognitive and computational representations’ and processes for the same and for similar consonant clusters according to their appurtenance to a) or b) or c).

The central hypothesis which we test is that speakers not only reactively exploit the potential boundary signalling function of clusters that result from morphological operations, but take active measures to maintain or even enhance this functionality, for example by treating morphologically produced clusters differently than morpheme internal clusters in production or language acquisition. We call this hypothesis, the ‘Strong Morphonotactic Hypothesis’ (SMH) (Dressler et al. 2006, Dressler, et al. 2010).

In particular, we suppose that sequences of phonemes exhibiting morpheme boundaries (the ‘morphonotactic clusters’) should provide the speakers with functional evidence about the morphological operation occurred in that sequence; such evidence should be absent in the case of a sequence of phonemes without morpheme boundaries (the ‘phonotactic clusters’).
Hence our idea is to investigate the psycho-computational mechanisms underlying the phonotactic-morphonotactic distinction by approaching the problem from two angles simultaneously: (a) psycholinguistic experimental study of language acquisition and production and (b) language computational modeling.

1An equivalent example for French language is given by a) prise (‘grip’, exclusively phonotactic cluster), b) affiche+ rai (I (will) post’, exclusively morphonotactic cluster) and c) navigue+ rai (‘I (will) sail’) vs. engrais (‘fertilizer’), the both conditions are true with morphonotactic condition as dominant.