Geometric Constraints on Human Speech Sound Inventories

Abstract

We investigate the idea that the languages of the world have developed coherent sound systems in which having one sound increases or decreases the chances of having certain other sounds, depending on shared properties of those sounds. We investigate the geometries of sound systems that are defined by the inherent properties of sounds. We document three typological tendencies in sound system geometries: economy, a tendency for the differences between sounds in a system to be definable on a relatively small number of independent dimensions; local symmetry, a tendency for sound systems to have relatively large numbers of pairs of sounds that differ only on one dimension; and global symmetry, a tendency for sound systems to be relatively balanced. The finding of economy corroborates previous results; the two symmetry properties have not been previously documented. We also investigate the relation between the typology of inventory geometries and the typology of individual sounds, showing that the frequency distribution with which individual sounds occur across languages works in favor of both local and global symmetry.

The organization of sound inventories: A study on obstruent gaps

“…Mackie and Mielke (2011) finds that attested inventories in P-base (Mielke, 2008) are more economical than randomly generated ones, based on four different kinds of economy metrics. Dunbar and Dupoux (2016) also have similar findings with similar simulation-based methodology.…”

“…Clements (2003b) states that feature symmetry may be conceptualized as a tendency for languages to avoid having gaps in their inventory. This notion of symmetry is further developed and tested by Dunbar and Dupoux (2016), where they propose two non-equivalent but related symmetry metrics: local symmetry and global symmetry.…”

“…For FEATURE-SYSTEMIC models, the gap is the sound whose presence in an inventory would decrease the overall goodness of the inventory based on some feature-based metrics. Three metrics are used in this study: feature entropy (Mukherjee et al, 2007), local feature symmetry, and global feature symmetry (Dunbar and Dupoux, 2016). Feature entropy is taken as a measure of feature economy: the feature representation of a system is more economical if it can be expressed by fewer bits.…”

Consonant co-occurrence classes and the feature-economy principle

“…This idea goes back at least to early work in structuralist phonology, including Trubetzkoy (1939), Martinet (1952) and Hockett (1955), who were interested in the extent to which phonological inventories are symmetrical with respect to features, or, in other words, how much 'mileage' phonological inventories get out of individual features; see an overview of early developments of this concept in Clements (2003). Similar conclusions were later reached using different formulations and/ or different datasets (Marsico et al 2004, Coupé et al 2009, Mackie & Mielke 2011, Moran 2012, Dunbar & Dupoux 2016, and theoretical and experimental investigations of feature economy have become a major line of phonological research: see Pater (2012), Verhoef et al (2016) and Seinhorst (2017).…”

“…In order to investigate this, we propose to first reformulate the principle in a more structural fashion. Building on the notion of sound-inventory symmetry explored by Dunbar & Dupoux (2016), we operationalise the feature-economy principle by interpreting it as largely synonymous with the layering principle : new classes of sounds arise by virtue of adding new features to already existing combinations. An empirical confirmation of this is found in Moran (2012: 248) with respect to vowels, such that ‘once languages expand their inventories beyond cardinal vowels, they tend to do so by either nasalization or lengthening, and to a lesser extent by adding diphthongs to the inventory’.…”