Introduction to Language Processing and Acquisition
Senior 6 · Psychology (Languages)
Introduction to Language Processing and Acquisition
Lesson 1 of 4
25 min
In 1976 Harry McGurk and John MacDonald, in Scotland, were studying how infants perceive speech when, by accident, a video was dubbed with the wrong sound: a woman’s voice saying “ba-ba” over her lips saying “ga-ga”. Watching the result, the researchers heard neither: they heard “da-da”. When they closed their eyes, they heard “ba-ba” again. Most adults they tested heard the blended syllable.
Figure 1. The McGurk effect.
The McGurk effect shows that understanding speech is not passive recording. The brain actively combines sound, sight and expectation to work out what was most likely said, in a fraction of a second. That active, fast, constructive work is what psycholinguists call language processing.
Definition
Language processing: the mental operations by which people perceive, understand and produce language in real time.
Comprehension: understanding language, from recognising sounds and words to building the meaning of sentences and whole texts.
Parsing: working out the grammatical structure of a sentence as it is heard or read.
Garden-path sentence: a sentence that leads the reader to an interpretation that turns out to be wrong, forcing a reanalysis.
Top-down processing: using knowledge and expectations to interpret input. Bottom-up processing: building interpretation from the input itself.
| Level | The task | Example question |
|---|---|---|
| Speech perception | Turning a continuous sound wave into speech sounds | How do we hear word boundaries when speech has no gaps? |
| Word recognition | Matching sounds or letters to words in the mental lexicon | Why are common words recognised faster? |
| Sentence processing | Building grammatical structure and meaning | Why do some sentences mislead us? |
| Discourse processing | Linking sentences into a coherent text or conversation | How do we fill in what is not said? |
| Production | Turning ideas into speech, writing or signs | Next lesson |
Spoken words run together without pauses; listeners split them using knowledge of the language. That is why an unfamiliar language sounds like one long stream. Recognition is extremely fast: according to William Marslen-Wilson’s cohort model, as soon as the first sounds of a word arrive, all words that begin that way become active (hearing “ele…” activates elephant, elegant, element), and candidates drop out as more sound arrives, often before the word ends.
Top-down knowledge can even supply missing sounds. In 1970 Richard Warren replaced one sound in the word legislatures with a cough. Listeners heard the complete word with a cough in the background and could not say where the cough had been. This is called phonemic restoration.
Read this sentence: The old man the boats. Most readers stumble, because they take “the old man” as a noun phrase. Read again: the old (old people) man (operate) the boats. A classic example from Thomas Bever (1970) is The horse raced past the barn fell, meaning “the horse that was raced past the barn fell”. Eye-tracking studies (Frazier and Rayner, 1982) show that readers slow down and look back at exactly the point where their first structure fails. Garden paths show that we build structure word by word, committing early to the simplest analysis, rather than waiting for the end of the sentence.
Comprehension needs background knowledge. John Bransford and Marcia Johnson (1972) read people a passage beginning: “The procedure is actually quite simple. First you arrange things into different groups…” Without a title, listeners found it confusing and remembered little. Listeners told beforehand that it was about washing clothes understood it and recalled about twice as much. Readers build a mental model of the situation, using what they know, and remember that model rather than the exact words.
Vsauce: “The McGurk Effect”, a one-minute demonstration. Watch with your eyes open, then listen again with your eyes closed, and note whether the syllable you hear changes.
Important
Evaluate the evidence. The McGurk effect has been repeated many times, but its strength varies widely between individuals and across languages; some studies found it weaker among Japanese and Chinese listeners than English listeners, perhaps because of cultural norms about looking at faces. Garden-path sentences are clever tools but rare in real life, where context usually prevents misreadings. Bransford and Johnson’s passage was deliberately vague, so it may exaggerate how much ordinary texts depend on titles; the general point, that background knowledge shapes comprehension, is well supported.
Warning
Common mistake: thinking that we understand speech one sound at a time, from left to right, using only the sound. Comprehension combines bottom-up input with top-down knowledge, and both work at the same time.
Tip
Exam technique: for any comprehension example, ask: Is this bottom-up (driven by the input) or top-down (driven by knowledge and context)? Most real examples involve both, so say how they interact.
Practice
Sources and credits
Written by Ganzaa: the text, the table, Figure 1 and the exercises.
