574. B. Ph LAB III 35. Accent (phonetics)

35.  Accent (phonetics)

Accent is the phonetic prominence given to a particular syllable in a word, or to a particular word within a phrase. When this prominence is produced through greater dynamic force, typically signaled by a combination of amplitude (volume), syllable or vowel length, full articulation of the vowel, and a non-distinctive change in pitch, the result is called stress accent, dynamic accent, or simply stress; when it is produced through pitch alone, it is called pitch accent; and when it is produced through length alone it is called quantitative accent. English has stress accent.
A prominent syllable or word is said to be accented or tonic; the latter term does not imply that it carries phonemic tone. Other syllables or words are said to be unaccented or atonic. Syllables are frequently said to be in pretonic or post-tonic position; certain phonological rules apply specifically to such positions. For instance, in American English, /t/ and /d/ are flapped in post-tonic position.
Some languages combine stress accent and pitch accent, in that accented syllables are both dynamically prominent and may have more than one tone, while unstressed syllables do not carry tone. An example of this is Serbo-Croatian accent. Such systems are typically called accent or pitch accent, as the latter term is not well defined.

Phonetic realization

The ways stress manifests itself in the speech stream are highly language-dependent. In some languages, stressed syllables have a higher or lower pitch than non-stressed syllables – this is called pitch accent (or musical accent).

Other features that may characterize stressed syllables include dynamic accent (loudness), qualitative accent (differences in place or manner of articulation, typically a more peripheral articulation), and quantitative accent (syllable length, equivalent to agogic accent in music theory).

PROSODY: FORM AND FUNCTIONS

• suprasegmental features (also prosodic or nonsegmental features)

– usually not easily identified as discrete segments

– can extend over longer stretches of speech

– tend to be directly related to higher levels of linguistic organization, e.g., information structure

• prosody as a continuum of functions and effects:

– extralinguistic: functions of anatomy, habitual characteristics, e.g. phonation quality

and pitch range as determined by anatomy/tensions of the larynx or long-term articulatory settings (tongue root posture, articulation rate)

• no conscious control by speaker

• communicative information: identity of speaker/class of speakers

– paralinguistic: use of overall voice quality, pitch range, pitch movement and

articulation rate to indicate a general attitude (excitement, seriousness etc.) or

certain sentence parts (via tempo and pauses)

– linguistic: stress, intonation, tone, length used to contribute or determine discourse

organization, discourse meanings, or lexical distinctions

PITCH

• most salient determinant of prominence, i.e., stress

• perceived correlate of fundamental frequency (number of times per second the vocal folds complete a vibration cycle)

• control of pitch (deliberate lowering or raising):

– laryngeal adjustments (tensing or relaxing of larynx/cartillage muscles)

– control of subglottal pressure (responsible for ca. 5-10% of the total range of pitch change in normal speech in English)

• changes in pitch as little as 0.3-0.5% are perceivable in frequencies below 1000 Hz

• resolution is best up to 500 Hz, still good up to 3000 Hz, worse up to 5000 Hz• thresholds of frequency perception: 20-20000 Hz

DURATION

• related to larger context of time, timing, and speaking rate

• intrinsic duration of sounds: short/long vowels, nasals usually long, voiceless fricatives longer than voiced ones, stop releases very short etc.

• biomechanical constraints: /a/ in “bat” longer than /ɪ/ in “bit” due to longer jaw movement

• syllable duration as main aspect of rhythmic structure

– English: vowel longer when followed by voiced consonant

– stressed syllable/vowel longer than unstressed one

– syllable (and all segments) shorter in faster speech

– syllables lengthened in phrase-final position

• listeners able to distinguish minimum relative differences of 20 ms at frequencies between 500 and 1500 Hz

LOUDNESS

• perceptual correlate of intensity (magnitude of sound pressure variation)

• primarily controlled by subglottal pressure, influenced by natural sonority of segment types

• correlated with stress, but less salient and consistent than pitch and duration

• auditory system responds to differences in loudness logarithmically (decibel scale)

– relative scale: 0 dB corresponds to the sound pressure level of a reference sound (usually close to the limit of detectability at 1 KHz)

– doubling of loudness corresponds to a 10 dB rise

– countryside at night: 20 dB, whisper: 30 dB, quiet conversation: 50 dB, normal conversation: 70 dB, damage threshold: 120 Db

WORD ACCENT

• lexical stress: one syllable of a word is more prominent than the others (except for monosyllabic words of course)

• language typology of ways of realizing word accent:

– Tone Languages:

• every stressed syllable has significant contrastive pitch, thus words are distinguished

• Contour Tone Languages: shape of the pitch contour is relevant

– e.g., Thai: mid khaa “to be lodged in”

low khàa “aromatic root”

falling khâa “servant”

high kháa “to do business in”

rising khǎa “leg”

• Level Tone Languages: only pitch level is relevant – e.g.,

Yoruba low īgbà “climbing rope”

mid īgbā “two hundred”

high īgbá “calabash”

– Pitch Accent Languages:

• specific pitch accent associated with certain syllables

– e.g., Swedish: Accent 1(fall): tan´ken (“the tank”); Accent 2 (rise-fall): tanˇken (“the thought”)

– Stress Accent Languages

 one syllable receives more stress/energy than the others in the word

TONE INVENTORY

• Pitch accents: H*, L*, L+H*, L*+H, H+!H*

• * indicates which target is associated with the accented syllable)

• H tones can be downstepped (!H)

• Phrasal tones

– Phrase accents (ip-boundary): H-, L-

– Boundary tones (IP-boundary): H%, L%

– Four possible combinations associated with specific discourse situations

• H-H%: strong final rise 􀁰 Yes/No-questions

• H-L%: high plateau 􀁰 calling contour/exclamation

• L-H%: late final rise 􀁰 continuation rise

   L-L%: final fall 􀁰 declaratives, wh-questions