William F. Katz

Phonetics is the scientific study of speech sounds. Phoneticians are interested in how people produce and understand speech sounds. Using symbols from the International Phonetic Alphabet (IPA), phoneticians transcribe the sounds of any languages in the world. Here are some important phonetic terms to help you, all described in plain English.

Phoneticians use the International Phonetic Alphabet (IPA) to distinguish sound substitutions (one speech sound switched for another) from distortion (slurring or mistiming) errors. This information is helpful to pinpoint the level at which a patient is making speech errors. The following terms can assist you in working with individuals with speech and language problems: Aphasia: A language disorder in adults resulting from brain injury or disease in which speaking and listening may be affected.

A source-filter system produces human speech. Speech begins with a breathy source. The airflow beginning at the lungs causes sound to be produced through vibration and hissiness at the larynx (also referred to as your voicebox) in your throat. You then shape this sound through a filter, the passageways of the mouth and nasal cavity (nose).

You make consonants by completely or partially blocking airflow during speech. You can do this in different ways: you can completely block airflow, push air through a groove or slit to make a hissing sound, block air then make a hiss, or bring the speech articulators (the organs of speech) close together to shape sound.

You make vowels in a different way than consonants. Vowels don't involve air blockage, but instead require a more continual sound flow and sound shaping. Phoneticians describe vowel production in terms of HAR: Height (whether the tongue is high, mid, or low in the mouth) Advancement (how front or back the tongue is) Rounding (whether the lips are protruded, for sounds like the "oo" of "boot.

Phonetics has come a long way since the good ol' days of Daniel Jones and his colleagues in London at the turn of the century. Technology and mass communication have revolutionized the field of phonetics, allowing breakthroughs the founders would never have imagined. The following previews some of these amazing new directions.

Phoneticians transcribe connected speech by marking how words and syllables go together and by following how the melody of language changes. Many phoneticians indicate pauses with special markings (such as [ǀ] for a short break, and [ǁ] for a longer break). You can show changes in with a drawn line called a pitch plot or by more sophisticated schemes, such as the tones and break indices (ToBI) system.

Spectrograms make speech visible and are one of the most popular displays used by phoneticians, speech scientists, clinicians, and dialectologists. A spectrogram is a readout that shows frequency on the vertical axis, time on the horizontal axis, and amplitude (amount of sound energy) as either darkness or coloration.

To make sure the information in Phonetics For Dummies is technically correct and as clear as possible, the author reviewed the title again after publication. The errata document clarifies some points and corrects errors that appeared in the first printing, despite the best efforts of the author and publisher. For access to the errata, click here.