Which term describes an inventory of word knowledge, spoken or written?

The term that describes an inventory of word knowledge, whether spoken or written, is lexicon. Lexicon refers to the complete set of words in a language, or an individual's vocabulary, which encompasses not just the meanings of words but also their uses in context. A rich lexicon is essential for effective communication, as it allows an individual to express thoughts clearly and understand the language of others.

In contrast, phonology pertains to the study of sounds in a language and how they function, rather than the words themselves. Articulation refers to the physical ability to produce sounds and words, while echolalia involves the repetition of phrases or sounds heard from others, often without comprehension. These other terms focus on different aspects of language and communication, which is why lexicon is the most accurate choice for describing an individual's inventory of word knowledge.