|CS 224S/LINGUIST 281   -     Winter 2009
Homework 1: Articulatory and Acoustic Phonology
|Due: January 13 at 3:14pm, i.e. before the start of class.|
Please read this entire page before beginning.
For these exercises, you may work in groups. Non-native speakers will probably need to team up with a native speaker. But do your write-ups separately, as discussed in the Homework Collaboration Policy
(1.1) Call the GOOG 411 service at 1-800-466-4411. Try to find a type of business or restaurant. Try to "barge in" (i.e. talk while Google is talking to you). Comment on any errors or misrecognitions that occur, as well as any weirdness in the interaction.
(1.2) Call the "TellMe" speech recognizer at 1-800-555-TELL and ask a question (stock quote, travel, etc). Try to "barge in" (i.e. talk while TellMe is talking to you). Comment on any errors or misrecognitions that occur, as well as any weirdness in the interaction. Compare your experiences with TellMe and Goog-411.
(1.3) Call the United Airlines automatic flight information, at 1.800.824.6200. Ask about a flight. Again, comment on any errors or misrecognitions that occur.
(1.4) Go to one of the TTS demo sites, ATT or IBM. Test out the site by choosing at least seven different sentences (paste them from another web site, or make up things). Try to be creative, including questions, exclamations, or whatever. Try at least two different voices. (You may have to choose "Download wav file" and play it twice, if the speech sound gets cut off as it plays the first time while it downloads.). Write down at least 5 errors that you hear; note whether these errors are in the phones, in the intonation/prosody, or something else.
(1.5) Find and correct the mistakes in the ARPAbet transcriptions of the following words:
(1.6) Transcribe the following words into the ARPAbet.
(1.7) Transcribe the following two wavefiles at the word level (that is, write down the words that occur in the utterance). Make sure to listen to them carefully and more than one time. If you have trouble listening to them, let me know immediately.
(1.8) Now open both files in Praat, the speech analysis program we used on class on Thursday January 8. Transcribe both files into the ARPAbet, using Praat to help you play pieces of each wavfile, and to look at the wavefile and the spectrogram. (In fact, you can use Praat to play the files for exercise 1.4 as well).
Turn in the ASCII ARPAbet sequences for the two files (just type it into your homework answers). For the Switchboard file, also label the start and end and identity of each phone using the "Annotate" -> "To Text Grid", with just one tier for "phone" (you don't need to use a word tier). Include a picture of this Praat labeled file using the "Draw" window (select the Sound and TextGrid, then click Draw, then save as EPS. Convert the file PDF before you attach it, if you can.) (If the file is too long to read the fonts clearly in the "draw" window, just break it into 2 or 3 parts and attach separate pictures). This is very hard, so I don't expect you to be perfect, I just want to you try to listen carefully for what's happening in each file.
(1.9) Get the minimum and maximum pitch for the two files. Record the pitch range (range = max - min).
(1.10) What are some differences between the Boston News file and the Switchboard file, in terms of transcription differences, pitch range, or other things you noticed. Switchboard is human-human speech; Boston News is broadcast speech, which resembles human-machine speech. Could this play a causal role in the differences you found? How?
You may use an on-line ARPAbet dictionary to help you. Here is the CMU dictionary. But many or most words in the above sentences will not be the same as they are in the dictionary! So be careful not to just copy the pronunciation from the dictionary (besides the fact that CMU uses a slightly different version of the ARPAbet than the one in the slides from lecture 1)
Getting Praat: Praat itself is here, and is free and very simple to download, just grab the executable. It runs on most popular platforms.
A quick Praat intro, written by Edward Flemming, is here.
A longer Praat tutorial is here.
How to turn in the homework: