Language processing What are the components of language, and how do we process them?

Phonemes Most basic components of a language. Individual sounds What are the phonemes of English? What distinguishes them from each other?

Phoneme processing Perception Speed: Can process phonemes per second Categorical Perception: Speech sounds get categorized as one phoneme or another. No in- between. Ex: ‘r’ vs. ‘l’ to a Japanese speaker Production Co-articulation: We change the phonemes we actually use based on the other phonemes surrounding it in the speech stream

Morphemes Smallest meaning carrying units in a language –Root Words: simple words like “book”, “run”, etc. –Affixes: Things we attach to words to modify their meaning; “-s” for pluralization, “-ed” for past tense, etc. –Interesting note: While we have standardized the spelling of morphemes when written, that doesn’t mean they are always pronounced the same.

Morpheme processing Lexicon –Content morphemes: Morphemes that actually mean something. “-s”, “run”, etc. –Function morphemes: Morphemes that serve a gramatical purpose, but have no real meaning. “the”, “or”, etc. –People know roughly 80- to 100-thousand morphemes, stored in the lexicon.

Neurology of the Lexicon Aphasias are deficits of language arising from brain damage. They differ from agnosias in that patients can still exhibit non-linguistic knowledge of an object. –Semantic paraphasia is where patients make errors in production by substituting semantically related words to the one intended. –Semantic dementia: Progressive semantic disorder largely associated with damage to the left inferior temporal lobe.

Broca’s aphasia Patients tend to have significant deficits in speech production; sometimes limited to producing only a single word or syllable. Even in less severe cases, production of function words is severely diminished. Also have a hard time understanding more complex syntactical structures, such as passive constructions. Corresponds with damage to the left inferior frontal lobe.

Wernicke’s aphasia Patients experience significant difficulties in understanding either written or spoken speech. Speech production is fluent and grammatical, but nonsensical. Single word production tends to exhibit semantic parahpasia. Wernicke’s area is located in the posterior temporal lobe.

Conduction aphasia Neural pathways in the arcuate fasciculus connect Wernicke’s area to Broca’s area (one-way). When this pathway is damaged, patients have difficulties with word usage. The also have difficulties repeating things they heard, or spontaneously generating speech.

Syntax Syntax (grammar) is the set of rules for combining morphemes. It gives language its meaningful structure. Are all languages derived from a common universal grammar? –Chomsky thought so.

Phrase structure grammar Phrase structure rules are rules for deconstructing complex symbols into sets of simpler symbols. S-> NP VP NP-> (det) (AdjP) N (PP) VP-> (AdvP) V (NP) (PP) det-> a, an, the Knowing the phrase structure of a sentence allows us to disambiguate it: They are cooking apples. Bob greeted his friend by the mailbox

Transformational grammar Chomsky said phrase structure grammars were too simple. How can we capture the semantic equivalence of syntactically different sentences? Bob threw the frisbee. The frisbee was thrown by Bob.

Neurology of syntax Agrammatic aphasia exists in patients who do not appear to have semantic deficits, but have significant difficulty in understanding sentences. They largely produce very short, agrammatic sentences similar to those of a child.