Language is an integral part of what it is to be human. It is a physical reality. Ironically, although it is such a large part of our daily lives, we do not intuitively perceive it as something that we can observe, something about which we can conduct experiments and make scientific observations. This thesis shows that language can be observed and that meaningful and interesting claims can be made about it.
In this thesis, the claims are formed in the framework of physics and using its scientific tools. Speaking about language may strike some as a poetic pursuit - or even an ineffable one - but we believe it actually invites the rigor and elegance possible within physics.
Beginning with the assumption that language is a physical phenomenon, we conclude with a theory that explains the way it has emerged and developed across time and place. In the process, we uncover some startling facts that support our approach. Specifically, the language of physics that we engage here examines the phase transition from crude wielders of a proto-language to the subtle users of a complex grammatical system. The kinds of transitions that occur in the dynamics of language are familiar to us because they occur in many other physical systems.
All of us who have watched ice cubes melting in our scotch have observed a phase transition, in this case, a structural change in the arrangement of water molecules from crystal to fluid. More broadly, a phase transition is associated with a change in a state variable. Consider the spatial relationship between molecules of a substance such as H2O. Emergent properties can be the consequence of a ``transitional process''. Referring back to our drink example, the emergent property is the amorphous fluid quality of water. We will invoke this vocabulary in our theory of language behavior.
Should we leave our scotch sitting too long on our desk, we will see the ice demonstrate the features of phase transition. In other words, the ice will change completely from crystal to liquid form. In the process some features are lost such as the presence of a solid and a clear distinction between water and alcohol. We will experience the results of attenuation - much to our dismay - should we now take a sip of our diluted drink.
Attenuation, we will show, is a key concept in our language theory. It is the erosion of perceptual structures - synaptic features - that distinguish usages between instances of vocabulary. To help define attenuation we rely on a diachronic account of language that begins with lexical vocabulary. Attenuation is a process that provides for the shareability of language and promotes structural changes in several aspects of linguisticity such as syntax, morphology and phonetic features. To demonstrate our claims, we employ a well understood and formally tractable computational model known as the Ising model. It is often associated with the modeling of structural changes in a system. The usefulness of the Ising model is in its simplicity and its mathematical predictability. Our thesis endeavours to unpack this terminology and make meaningful our claim that fundamental structural changes can occur in language without changing the basic nature of the system, that even the most primitive utterances can give rise to complex grammatical structures.