Structural and Functional Organizing Principles of Language: Evolving Theories

The overall goal of this paper is to evaluate theories that attempt to address the organizing principles of language and review the development of these theories toward the integration of language within an interactive network of higher-level cognitive functions. Commencing with an overview of traditional concepts of language as modular, distinct, and innate, we focus firstly on areas that highlight the foundation of modularity theory including various module definitions and criteria, and applications of modularity in information processing and biological systems. We also discuss challenges to the overall applicability of a modular system and limitations of modular models in dealing with adaptation, novelty, innate versus learned, domain-general and domain-specific features, and developmental and age-related changes of cognitive organization. Prompted by the rapidly increasing amount of empirical data on the functional elements of the human brain, we then evaluate several major theories of cognition, including views that oppose modular organization and those that integrate modular and semi-modular views with topological modularity in simpler, and dynamic integration in higher-level cognitive functions.Within this framework, modular and non-modular components of linguistic knowledge, organizing principles of language viewed either as specific or derived from other systems, and concepts of language as one of the cognitive functions or the outcome of unique interactions among cognitive components are discussed. Emerging theories that integrate interactive network models support a cognitive architecture as a mosaic of domain-specific and domain-general processes involving both functional segregation and integration within a global neuronal workspace. Within this anatomically distributed workspace, the language function represents unique interactions among cognitive components consistent with an organization that is task-dependent with a continuum between degrees of modular and shared processing. As a higher-level, learning-based, and effortful cognitive process language transiently enlists a less modular organization for an efficient network configuration in interaction with several cognitive systems and the domain-general cognitive control/multiple-demand network.