Which term relates to the science of speech sounds and their development in language?

The term that relates specifically to the science of speech sounds and their development in language is phonology. Phonology involves the study of how sounds function within a particular language, how they pattern, and how they are used to convey meaning. It analyzes the rules governing phonetic sounds, including their distribution, organization, and transformation, which are essential for understanding language and communication.

Hyperlexia refers to an advanced reading ability often seen in some individuals with autism, but it doesn't directly relate to the scientific study of speech sounds or their development. Linguistics, while a broader field that encompasses all aspects of language, including phonology, syntax, semantics, and pragmatics, does not specifically target speech sounds alone. Echolalia describes the repetition of phrases or sentences, often observed in certain developmental contexts, but is not focused on the scientific study of speech sounds.

Overall, phonology is the most precise term when discussing the science of speech sounds and their role in language development.