Sound and Speech

The vocal tract Figures from Graddol et al.

Manner and place of articulation f s t p

Classification by distinctive features SoundVoicingPlace of articulation Manner of articulation f voicelesslabio-dentalfricative v voicedlabio-dentalfricative p voicelessbilabialPlosive/stop b voicedbilabialPlosive/stop

English consonants as combinations of distinguishing phonological features

Transitional sounds in ‘cleaned’

Some definitions Phonemes - significant sounds used by a speaker Phonetics - physical properties of speech sounds Phonology - functional organisation of sounds in a particular language or dialect. Prosody - pitch, loudness & duration of speech sounds

Speech Perception From Wikipedia

Speech perception tasks of a speech comprehension system: –isolate phoneme from sound –required capability: –segmentation and categorisation of sounds problem: variability solution: categorical perception

Categorical perception Consonants differ in place of articulation –/b/, /d/, /g/ Or voice onset time –/b/, /p/ /d/, /t/ The variation is continuous between these, yet they are perceived as categorically distinct. uber v. über

Context Phonetic restoration effect –It was found that the *eel was on the orange –It was found that the *eel was on the axle –It was found that the *eel was on the shoe –It was found that the *eel was on the table (Warren and Warren, 1970)

Prosody Rhythm –Syllabic stress –Sentence focus I bought potatoes –Stress - intensity, duration and pitch of sound –Intonation - relative changes in pitch –Pitch contour

Tracing of a pitch contour

Pitch and stress

Functions of prosody Given and new information Presuppositions –I didn’t do it Illocutionary force –Questions, directives, assertions, etc. Attitude Conversational management –Turn taking

From sounds to words Two options: –immediately from phoneme to lexeme –from the phoneme via the syllable to the lexeme Tasks: –Access (searching for lexemes) –Selection (... of the target lexeme) –Integration (connect to lemma) Timing: –starts at the first phoneme encountered For clarification purposes: –Lemma: The lemma can be compared to an entry in a dictionary. It combines a semantic concept with a basic word form. The lemma also contains information on word class (Noun, Auxiliary, Verb, …), gender, and possible syntactic context. –Lexeme: The lexeme relates lemma-information to sounds (or letters in written language) and a syllable structure. It also calls up inflectional information with respect to the actual utterance under production. That is, roughly, the lexeme relates lexical information, grammatical information, and phonetic/phonological information.

From sounds to words – ctd. Reconstructing the process: –Priming-Experiments: target word is found quicker with same initial sound cluster no influence, however, of identical final cluster (rhyme) –Gating-Experiments: (target word presented sound wise in steps of 50msec) subjects identify target words before their final sounds; possible reason: redundant information towards the end of a word (in e.g. English or German) Gating-Experiments revealed three main steps: –a linguistically determined point of discrimination at which the word is singular –a point of word recognition at which subjects correctly identify the word (may be before or after the point of discrimination) –the point of isolation at which subjects decide on a target word; this decision may be wrong additional information such as frequency information has to be involved, too, since word recognition can happen before discrimination

From sounds to words: The process Cohort/Model (e.g. Marslen-Wilson&Tyler 1980) –Initial sound activates all lexemes beginning with this sound: the initial cohort –search stops as soon as only one candidate form remains –advantage: the speech comprehension systems gains time for subsequent processing steps, because the search can be stopped before the complete soundform has been analysed –Example: El... Ele... Eleph... –Problem: deficient input –defects at the beginning of words disable correct access of target lexemes this led to Cohort II: –includes top-down flow of information: target lemma is involved in selection, e.g. by activation through contextual information (sentence internal or external)