Guidelines for Phonetics Project

Introduction to Phonetics, L541
Robert F. Port
Indiana University, Bloomington, IN
(revised Jan 29, 1998)

1. The Course Project

In this phonetics course, each student will conduct an original research project relating to some topic in phonetics. Students will be put in groups of two or three to decide on a research topic and conduct research. Although the research itself will be a group effort, each student is expected to submit his or her own write-up of the experiment. Group members may discuss their results and share any graphs or tables, but the paper text itself should be an independent effort!

The following steps should guide you in developing your project idea:

1) Formulate a research question relating to a topic in phonetics. The simplest is simply to examine a phonological contrast -- eg, showing what the differences are between some minimal pairs.You are encouraged to investigate a language other than English, however make sure there are a sufficient number of speakers available in Bloomington. Try to develop a topic for which at least 3 speakers can be found.

2) Topics should be developed in consultation with the instructors before research is begun. Port will meet with each group a time or two to get your project idea sharp and to help suggest modifications that will make it easier to get good results. Consult with Port again as soon as you have a preliminary interpretation of your data.

3) An analysis of your data should be conducted using equipment in the Phonetics Lab. . To keep your project manageable in size, try to use not more than 15 to 20 utterances per speaker, for a total of 100 to 200 utterances for measurement.

4) Your data should be presented in some appropriate statistical format, including relevant graphs or tables. It is nice to do some statistical tests, if you know how to do them, but it is not required. Hopefully the results will be so obvious, that statistical tests are not essential.

5) A thoughtfully-written, typed descriptions of your project should be handed in before the end of the semester. Your paper should have roughly 8 pages of text, plus tables and graphs (normally each on a separate page).

2. Designing Your Experiment

Hints on devising test materials.

1) If you are looking for a particular effect, attempt to find ways to make your effect as prominent or exaggerated as possible. Once you have demonstrated some effect, then more subtle experiments can be done to examine context effects.

2) Make sure that the target word or words are placed in a phonetic environment in which they will be easy to measure. For example, it is easy to mark the boundary between [a] and [s]; it is NOT easy to mark the boundary between [a] and [j]. This will become clear once you have looked at some spectrograms. If you are measuring formants, it will be easier to do with a low fundamental frequencies (and thus easier with male speakers).

3) Embed your test words near the middle of a sentence rather than at the beginning or end. Words in sentence-initial and sentence-final position tend to have quite distinct and nontypical pronunciations. For example, it is also difficult to mark the onset of a sentence-initial stop.

4) If your test sentences would reveal obviously to your subject what exactly you are looking at, you should probably include superfluous sentences so that your goal is not so obvious. This measure will help prevent your subject from exaggerating or biassing their productions in order to `help you out'. Do not tell them until the experiment is over what exactly you are looking for.

5) When speakers are presented with a list of sentences, their intonation often follows a predictable, list-reading pattern. Since their intonation is likely to be different at the very beginning and very end of the list, put dummy sentences in these places that you aren't going to measure.

6) Similarly, in order to average out any differences based on the location of a sentence within a list of sentences, it is a good idea to randomize the order of sentences for each subject. Or present the items in several random orders. This will hopefully even out any effects of position in the list and distribute the effect across all the test items.

Recording the speakers.

1) Make sure you get to the lab about a 1/2 hour earlier than your subject to avoid potential embarrassment and irritation to the subject. Remember the lab might be locked or somebody else using the equipment, etc. Be sure to try actually recording something and playing it back to make sure the machine is set up properly.

2) Although you do not need to do this for these course projects, keep in mind that in publishable research in this country, it is now expected that all subjects will sign an `Informed Consent' statement agreeing to participate in the experiment subject to a number of conditions that are spelled out. Normally the experimenter promises to either destroy the records after completion of the experiment or to preserve confidentiality. Subjects are assured they may leave the experiment at any time for any reason without penalty, and so forth.

3) Make sure you have tried out your task yourself. Decide just where you need little breaks and some bigger breaks from the task. You want the subjects to be comfortable. Think about whether they need time to pause, clear their throats, or even get a drink at some point.

4) While recording them, listen carefully to your subjects to make sure they are giving the kind of speech you want. Don't be afraid to tell them what to do, and ask them to repeat anything that is not done correctly. Most people are pleased to be asked to serve as speakers of their language.

5) Have your speaker practice the reading task before you begin recording. This gives the speaker time to feel more comfortable, it gives you ample opportunity to make sure they are doing what you want (and it is a good opportunity to adjust recording levels, etc).

6) Have your speaker produce more repetitions than you need. It is time-consuming to have a speaker come in a second time, and you don't have to measure everything you record (though you should choose which ones to measure according to a criterion that you report).

7) Make sure you are actually recording!

8) Leave plenty of leader tape at the beginning and end of your tape so that it will be easier to manipulate when you use it again for dubbing.

Use of the laboratory in 331 MH:

1) Sign up for lab time outside the door to establish your claim on the room.

2) If you plan to come in at an odd hour--evenings, weekends, or very early morning-- make sure you get a lab key from Port or the Dept office - or have make arrangement to meet someone who has a key. The outside doors to Memorial Hall are often locked on Saturday and Sunday, and is locked every night after about 9pm. Usually, in evenings and weekends you can get in by waiting a couple minutes til someone with a key enters the building.

3) Please be VERY careful about security. The lab contains many items that are very attractive to thieves.

3. Writing the Manuscript

Writing an experiment report is a very stylized genre of writing. It should be as efficiently written as possible and should provide each item of information just where readers will expect it to be. Nothing redundant. The paper should contain 6 sections: a short Abstract, an Introduction, Methods, Results, Discussion and Conclusions. The Bibliography, Tables, Figures and typically come at the end (though the Tables and Figures can also be inserted within the text).


Always include an abstract for ANY paper (in my opinion). Write it as one paragraph, about 200 words or less. This is a concise summary of the entire experiment. Include the rationale, method, results, and significance in highly abbreviated form (but using full sentences). Look at some published journal abstracts or Acoustical Society Meeting abstracts to get the idea of how to write one.


Give background rationale for the experiment. Why were you motivated to do this experiment? Or more accurately, given what you actually found: Why MIGHT you have wanted to do this experiment? Your report, in other words, should not be biographical or historical. Experiments in phonetics are often exploratory; we often are not testing a specific hypothesis. And, in any case, readers really don't care what you THOUGHT you might find but did not. The paper should tell a story about what the data actually show. Summarize results of earlier research that are necessary to account for the conduct of the experiment (as relevant to the interesting aspects of your results) and help the reader to able to have some expectations about what the experiment will show (whether right or wrong).

Pay attention to your use of verb tenses in the text. It is easy (but confusing to readers) to slip back and forth between `The subject read the words at two rates' and `We measure the duration of the vowels by ...'. Avoid this.

The last paragraph before the Methods should sketch in readable style the basic logic of the experimental design to come. Eg, ``Thus, in the following experiment, Ss were asked to read words with both voicing values in position X at two speaking rates in order to see whether rate has an effect on the ratio of the vowel duration to consonant duration. We expected to find no difference in ratio due to speaking rate.'' (Or whatever.)


There are 3 logical parts to the methods: the Independent Variables (input variables), the Task performed by the subjects, and the Dependent Variables. You have a task (eg, reading these phrases in a some way) for which certain values of the IVs are set (eg, +/-voice, +/- front, final stops at two speaking rates, etc.). Then you measure the DVs (eg, vowel durations, F0 contours, whatever). Finally you look for ways in which the DVs are structured by the IVs. This section should be tight and business-like in style.

Of course, you need to tell your readers about at least the following:


Systematically go through the relevant aspects of your data. Present tables and graphs of the DVs. The organization of these paragraphs will probably be in terms of the IVs. (For example, "The change in value of voicing affects both vowel duration and consonant closure duration," rather than "The vowel duration is affected by speaking rate, vowel identity and voicing".)

Describe the important features of the data in the text. Lead the reader through the tables and figures (eg, "As can be seen in the left side of Figure 1,..."). Devise data presentation techniques that make the real meaning of the data as clear as possible. Be sure to label graphs and figures clearly. Organization of paragraphs would normally be in terms of the independent variables.


1) Organization of paragraphs (subsections) may often be in terms of independent variables (i.e. the factors varied in the experimental design).

2) Compare your results to previous similar experiments. To what extent do your results resemble those found before?

3) What new discoveries have you found? What is their significance to specific and more general issues in the area?


Review and summarize very briefly what was done in this experiment and what you found in the results. State in general terms the most important discovery in the experiment. You may also want to suggest follow-up experiments.

4. Notes on Experimental Writing Style

1) Avoid first person pronouns no matter how awkward it may seem. "I asked the Ss to..." => "The Ss were asked to...".

2) Paper is cheap! It is easier to spread out your text and figures and use many separate pages.

3) Be as pithy as possible. Learn to use standard verbal formulas to abbreviate descriptions of methods, statistics, etc. Never be concerned that your paper is too short. It can only be too long. Say everything you have to say and no more. If you want to stretch out your paper, do it in the Discussion-- keep the Methods and Results tight, systematic and predictable.

4) Make a careful outline that you update as you write. It's generally easiest to write the Methods first, then Results (starting a new page), then sketch out the Discussion (starting a new page), and finally create an easily read and descriptive title. Then write the Introduction last.

5) When completed, the order of parts should be: Abstract, Text, References, Tables (on a separate pages unless very small), Figures (each on a separate page unless very small and labeled at the bottom). All tables and figures need a legend (on the page or listed on a separate page). Staple on diagonal in upper left hand corner. No fancy covers or plastic folders! Typed, of course, and EVERYTHING DOUBLE SPACED.

6) Use plenty of Figures! Be creative with figures to facilitate the reader's understanding.

But most of all HAVE FUN.

Jan 29, 1998