EMG assessment

2011 assessment tasks

You submission for this workshop:

• must not exceed four pages (single spaced A4 pages, 12 point font)
• should not  include the tables and figures provided in these web pages. Simply refer to a workshop image by number and describe carefully the features that you are referring to
• does not need to be written up as a normal experimental report. In other words, you don't need to reiterate the details of the experimental procedure nor do you need to copy the details of the results into your submission
• should be structured so that it covers the following points.

1) Introduction

Provide a brief overview of facial muscles and their function in producing phonetically relevant lip gestures. Also consider the neural planning of gestures and the timing of the selective activation and suppression of various muscles. Link this introduction to the following sections by outlining briefly the issues which are examined in this workshop.

2) Analysis of selected tokens

In your analysis of the specific tokens listed below you should be mindful of the following issues:-

• What are the relative levels of muscle activation from one phonetic class to another?
• What are the positions in time (relative to the speech waveform) of the various peaks and dips, noting whether the onsets of activation or inhibition are sudden or gradual?
• When two muscles are activated simultaneously are they acting in synergy or antagonism?
• What are the coarticulatory effects of one class of sounds upon another?
• Be careful to concentrate on the general trends of activity and to ignore the many minor peaks in each EMG trace.

Answer the following questions. You are free to make additional observations about other tokens if that helps you to answer these questions, but you must ensure that you particularly concentrate on the tokens referred to in these questions.

1. Compare the muscle activity for all of the isolated vowel tokens. Can you find muscle activity evidence for a separation of these vowels into lip rounded, lip spread and lip neutral phonetic classes?
2. Examine the muscle activity for the following tokens: /i:hi:/ /ʉ:hʉ:/ /i:hʉ:/ and /ʉ:hi:/. What's happening during /h/ in each of these tokens? Does this data provide any evidence that /h/ is  a lip-neutral consonant? Can you find evidence in any of these tokens that /h/ belongs to the second syllable?
3. Examine the following tokens: /i:bi:/ and /i:pi:/. Describe the sequence of muscle activity during and immediately before and after these oral stops. Discuss whether there are any significant differences between voiced and voiceless bilabial stop muscle activity in this phonetic environment.

3) Conclusion

Conclude your assignment with a brief summary of the points covered in part 2. How do your observations align with the observations and conclusions of Öhman (1967)?