Graduate School of Language Technology

Nordic Graduate School of Language Technology

Speech Technology Level 1 (2007)

Practical assignment – Phonetic analysis

Each student should carry out an acoustic investigation of their own speech production including vowels and consonants. This exercise will make the student familiar with speech analysis and the basic structure of speech sounds. The results should be summarised and will be discussed by all students at the meeting in October.

Software

The analysis can be done with the help of the WaveSurfer software. It can be downloaded from http://www.speech.kth.se/software/#wavesurfer

Vowels

Question 1:

In what way do your own vowels differ in formant frequency from acoustic descriptions of vowels found in the literature? How can you account for these differences?

Procedure:

Make an analysis of your own vowel system. Record the different vowels using test words within a carrier sentence such as: “I said (testword) again.”

Measure the duration and formant frequencies of your vowels. Make a table with the measured values. Make an acoustic vowel chart of the first two formants by plotting F1 on the y-axis and F2 on the x-axis. Reverse the frequency scale so that the values decrease instead of increasing along the axes (see e.g. Johnson, p. 105). Compare the formant values of your vowels to published values.

Question 2:

In what way do your vowels differ acoustically when in stressed and unstressed positions? How can you explain this?

Procedure:

Make an analysis similar to that for question 1, but this time record instances of all vowels when they occur in both stressed and unstressed syllables. Measure the duration and formant frequencies of your vowels and make tables similar to those in Question 1.

Consonants

Question 3:

What acoustic features can you use to group your consonants into categories related to place of articulation, manner of articulation and voicing?

Procedure:

Record all your consonants in the context of the same vowel using a nonsense testword within a carrier sentence such as “I said /aCa/ again.” Make an acoustic analysis of the consonants with respect to e.g. fricative noise frequency, occlusion phase duration (silence), burst frequency, aspiration, nasal and liquid formant frequencies and bandwidth, formant transitions in the adjoining vowels.

Question 4:

In what ways can a consonant vary acoustically as a result of the phonetic context (different adjacent phonemes)? How can you explain this?

Procedure:

Choose one consonant and make recordings of the consonant occurring in different words where the neighbouring phonemes are different (e.g. different vowels before and after the consonant, different consonant contexts and in consonant clusters). Use real words in a sentence frame.

Special assignment

If the above is too simple for you, choose a specific question to study, such as the different realizations of /r/ or how the acoustic effects of rounding spread to adjacent segments in spontaneous speech.

Reference

Acoustic and Auditory Phonetics, Keith Johnson, ISBN# 0-631-20094-0 (a second edition is also available)

Teacher

David House davidh at speech.kth.se http://www.speech.kth.se/~davidh