Speech Perception Quiz

Language and the Brain - Part 1

• Learning Outcome: Understand processes involved in speech production and comprehension.

• Agenda: The Human Mind at Work

• Psycholinguistics: The study of how we use our linguistic knowledge in speech production and comprehension.

  • Focuses on linguistic performance (how we use language) and linguistic competence (knowledge of language).
  • Speech production involves accessing the lexicon (words), using grammar to form sentences, and producing sounds.
  • Speech comprehension involves accessing the lexicon and grammar to understand the sequence of words heard.

• Other Psychological Processes in Language: Various cognitive processes are involved in the production and comprehension of language.

  • These processes enable the breakdown of continuous speech sounds into meaningful units (e.g., phonemes, syllables, words).
  • Other mechanisms determine how words are pulled from the mental lexicon and assembled.
  • Typically, understanding and producing sentences happens without conscious effort or awareness. However, speech errors and comprehension difficulties can occur.

• Psycholinguistics & Sentence Examples:

  • Presenting three sentences, with the first example demonstrating a commonly perceived ungrammaticality which is perceived as grammatically correct in another example. This illustrates that language processing includes more than just grammar.

• Comprehending Speech Signals: Understanding sentences involves multi-level analysis of the speech signal.

  • The acoustic speech signal comprises fundamental frequency (pitch), intensity (loudness), and quality (differences in speech sounds).
  • Speech waves can be visualized as spectrograms (voiceprints).

Speech Perception

• Speech as a Continuous Signal:
  • Sounds in natural speech overlap and influence each other. This creates a "segmentation problem" for listeners.
  • Recognising discrete units (words, syllables, phonemes) through various listeners’ strategies to understand speech signals, including the segmentation problem and adapting to different speakers and contexts.
• Problems in Perception:
  • Speech perception mechanisms need to overcome variability and lack of discreteness in speech signals.
• Listener Adaptation:
  • Listeners quickly adjust to foreign accents and distorted speech.
  • Listeners rely on various acoustic cues in the speech signal.
  • Acoustic elements' relationships are exploited by listeners.
• Categorical Perception: Acoustic distinctions that language speakers perceive are not always as evident or clear as they may appear to or for the listener.
  • Language specifically affects how listeners perceive sounds or features, depending on their linguistic background or knowledge.
  • The perception of similar sounds as belonging to the same category is affected by language – listeners categorize spoken sounds to a specific category that depends on their language.
• Stress and Intonation in Perception:
  • Stress patterns and intonation contours signal syntactic constituents in the speech stream.
  • Words in phrases at the end tend to be longer in duration than at the beginning, and intonation cues mark sentence boundaries.
  • Listeners rely on lexical knowledge to identify words (lexical access or word recognition).

Language Comprehension

• Parallel Processing: Successful language comprehension involves many operations occurring simultaneously, termed "parallel processing".
  • Stages involved include: Segmentation, morpheme and word recognition, finding appropriate word meanings, placing words in syntactical structures, interpreting phrases and sentences, creating a mental model of the discourse, and contextualization.

Top-down and Bottom-up Processing

• Involving Both: Perception and comprehension rely on both bottom-up (building from the acoustic signal) and top-down (using higher-level knowledge) processing.
  • Top-down processing utilizes higher-level knowledge, like semantic, syntactic, and contextual information to process the acoustic signal.
  • Bottom-up processing uses the acoustic signal directly to build phonological representations, look up word meaning in the lexicon, and construct semantic interpretation.

Lexical Access

• Definition: Lexical access is the process of obtaining word information (meaning and syntactic properties) from the mental lexicon.
• Factors Affecting Speed:
  • The frequency of words in usage affects how quickly listeners respond to them or make a lexical decision (more frequent words faster access).
  • Words with larger phonological neighbourhoods (similar-sounding words) require more processing time than words with smaller neighbourhoods.
• Semantic Priming: Earlier word(s) heard can activate related words in the mental lexicon.
• Morphological Priming: A kind of semantic priming where a morpheme of a multi-morphemic word primes a related word (ex. sheepdog + wool)

Syntactic Processing

• Definition: Parsing involves determining the syntactic relations among words and phrases in a sentence.
  • It is heavily influenced by the rules of grammar.
  • Listeners actively build a structural representation of the sentence as they hear it; thus, they must determine the grammatical category and fit into the sentence's structure.
  • Determining syntactic relationships among words and phrases. Examples include ambiguous words like "fire" being a noun or verb.
• Ambiguous Words: Identifying syntactic and semantic contexts helps resolve ambiguity quickly.

Speech Production

• Stages: Sound organisation within words and within sentences is linear; pre-articulation / planning stages include units larger than phonemes.
• Spoonerisms: Speech mistakes revealing that planning involves larger units in language production.