What makes some sentences more difficult to process, and why? Memory- and expectation-based theories both attempt to explain sentence processing difficulties, and decades of sentence processing literature have found evidence in support of both theories. This dissertation further investigates these theories of sentence processing by exploring…

This dissertation investigates how the abstract representation of vowels affects spoken word recognition in Brazilian Portuguese and American English by examining two issues in theoretical phonology and speech processing: underspecification theory, and underlying representation when there is alternation. Three experiments were conducted in…

What is the nature of conceptual representations? Models of semantic memory often describe concepts as a distributed feature space. However, it remains unknown which subset of this feature space constitutes the invariant representation of a concept. In this dissertation, I investigate the nature of modality-independent representations and their…

Noise is a common impedance to easy and accurate speech understanding. In the presence of noise, speech processing mechanisms proceed with partial or ambiguous inputs, and listeners will engage additional cognitive resources to make sense of what they hear. The extent to which this is situation is affected by diminished exposure to a language is…

In standard models of language production or comprehension, the elements which are retrieved from memory and combined into a syntactic structure are "lemmas" or "lexical items". Such models implicitly take a "lexicalist" approach, which assumes that lexical items store meaning, syntax, and form together, that…

Most of the world's languages include multiple varieties and dialects. Individual ability to successfully alternate between these varieties can be a socio-cultural and academic necessity for many bilingual speakers, including children in the US who alternate between African American English (AAE) and Mainstream American English (MAE). This…

To build an Artificial Intelligence system that can assist us in daily lives, the ability to understand the world around us through visual input is essential. Prior studies train visual perception models by defining concept vocabularies and annotate data against the fixed vocabulary. It is hard to define a comprehensive set of everything, and thus…

Theoretical phonology has at its heart the assumption of two separate levels of speech sound representations: one less abstract, phonetic, 'surface' level, and one more abstract, phonological, 'underlying' level. Descriptions of phonological neutralisation processes such as German final devoicing hinge on the mappings between these two levels, as…

How do infants learn about the formal properties of language using only cues they can access in speech? And what intuitions do they bring to the learning problem? Chapter 2: To explore whether current notions of statistically-based language learning could successfully scale to infants' linguistic experiences "in the wild", we implemented…

Ambiguity is a natural part of language and in studying the comprehension and resolution of ambiguity in a second language (L2), we must consider the influence of the native language. This dissertation examines L2 processing of the lexical semantic ambiguities, homonyms and polysemes. These are words that share the same form but have different…

This dissertation delves into second language acquisition, sociophonetic variation, and speech perception, investigating how prior linguistic experiences and exposure to regional variations in a second language influence the decoding of dialectal linguistic cues. It aims to enhance the understanding of words pronounced with different phones and…

This study explored the role of artificial intelligence (AI)-powered conversational agents in human-computer interaction, particularly in the post-coronavirus (COVID-19) era, where digital technologies are central to healthcare, customer service, and education sectors. The research investigated the disruption of context continuity when users…

The dream of intelligent assistants to enhance programmer productivity has now become a concrete reality, with rapid advances in artificial intelligence. Large language models (LLMs) have demonstrated impressive capabilities in various domains based on the vast amount of data used to train them. However, tasks which require structured reasoning or…

In recent years, converging evidence has suggested that prediction plays a role in language comprehension, as it appears to do in information processing in a range of cognitive domains. Much of the evidence for this comes from the N400, a neural index of the processing of meaningful stimuli which has been argued to index the extent to which a word…

The rise of Artificial Intelligence technology has raised concerns about the potential compromise of privacy due to the handling of personal data. Private AI prevents cybercrimes and falsehoods and protects human freedom and trust. While Federated Learning offers a solution by model training across decentralized devices or servers, thereby…