L2 - Speech perception

Question 1

What is that journey of air from the lungs to create sound waves?

Answer 1

Air travels from the lungs, through the vocal tract, and out the mouth and nose.
Rapid pressure changes modulated by changes in the shape of the vocal tract form sound waves.

Question 2

What are the two main sources of sound and what are they responsible for?

Answer 2

The larynx is responsible for the characteristic pitch of a person, while constricting the lips, tongue and palate help to form phonemes.

Question 3

What are the two main problems in speech perception?

Answer 3

The segmentation problem and the variability problem.

Question 4

What is the segmentation problem?

Answer 4

• speech is not segmented (no spaces between them).

- usually we seperate words despite ambiguity, but sometimes there are problems (foreign languages, song lyrics).

Question 5

Why is the misinterpretation of song lyrics particularly common?

Answer 5

• 2 sound signals (music/words).
• rhythm of music changes (stress).
• tone of music changes (intonation).
• articulation may be imprecise.
• pragmatics/semantics of lyrics can be unusual.

Question 6

What is the variability problem?

Answer 6

• speech is highly variable.
  -> variability of phonemes, syllables, words - between and within speakers.
  Between: gender, accent, language.
  Within: coarticulation (‘t’ in ‘sweet’ vs. ‘little’), physical state, paralinguistic (speech rate, clarity).

Question 7

When are vowels more differentiated between?

Answer 7

Vowels are much more differentiated in speech to infants, than to adults or pets.

Question 8

What are the 3 ways which people solve problems of segmentation and variability?

Answer 8

• bottom-up information (acoustic info).
• top-down information (info in long term memory).
• multi modal (visual information ‘the McGurk effect).

Question 9

What is bottom-up processing?

Answer 9

• categorical perception of consonant phonemes.

- efficient, automatic categorisation into phonemes reduces confusion from ambiguity.

Question 10

What is lexical prosody?

Answer 10

The melody and rhythm related characteristics of speech.

• Intonation contour:
  
  • > a pattern of changing pitch which carries meaning.
• Rhythm:
  
  • > comes from the pattern of prominent vs. non-prominent syllables (supercalifragilisticexpalidocious).

Question 11

What is top-down processing?

Answer 11

The influence of information from knowledge and long-term memory.

• Lexical knowledge:
  -> hearing the same ambiguous sound differently in
  different contexts.
• Phonetic rules:
  -> combinations of letters that do not occur within words
  e.g. [stw] = mu(st)_(w)in
• Word context:
  -> Ganong effect: context consistency of ambiguous
  words “the lumberjack cut the woo_” (d/l).
• Sentence context:
  -> phonemic restoration effect.