Introduction to Linguistics, Session 9, Thursday, 2006-12-21

Introduction to Linguistics, Session 9, Thursday, 2006-12-21




PHONETICS II: REALISING SOUNDS

FOCUS on the transmission and perception of speech sounds!




1.) ACOUSTIC PHONETICS: Speech transmission

When the resonants source (F0) comes up from the larynx, it has to walk across different filters: the pharygnal filter and whether the oral filter or the nasal filter. Within these filters the air stream is changed to a complex sound wave of different frequencies (articulatory phonetics).
The complex sound wave that travels through the air can be analysed in a computer programme that is called PRAAT.

PRAAT offers the possibility to view sound waves in a spectogramme (which shows time, frequency and amplitude (dark shadings) of a specific sound wave) and in an oscillogramme (which shows time and amplitude).
But it does not show a spectrum which indicates both frequency and amplitude on its axes.

With PRAAT the learner can have a look at how fricatives differentiate physically from plosives (that have got an onset time) or vowels (that contain a lot of acoustic energy: represented as formants in a spectogramme). The learner can isolate specific sounds and have look on their realisation and their physical features.
This makes clear how the end and onset sounds of different words are enchained in English. In standard English, there is no glottal stop between single words as it is in German.

The learner can transcribe the spoken language in normal orthographical spelling and do a narrow transcription of the speech sounds.



2.) AUDITORY PHONETICS: Speech perception

The ear consists of three main parts: the outer ear, the middle ear and the inner ear.
When a sound wave reaches the pinna, the hearing process begins. Sound waves travel the auditory canal and go through the tympanic membrane of the eardrum into the middle ear. Hammer, anvil and stirrup, three bones that are situated in the middle ear function as a lever for the acoustic income.
They can amplify or dampen the amplitude of sound waves in order to protect the inner ear (but this only works for certain frequencies).
The cochlea of the inner ear brakes up a complex wave into its single waves. In fact it, does a spectral analysis (spectral transform) like it is represented in the computer programme PRAAT.