Sounds, letters and the IPA

What phonology describes

Phonetics describes how a sound is produced and heard. Phonology asks how a language organizes sounds into contrasts and patterns. A speaker can produce two audibly different sounds without treating them as two different word-building units. Conversely, a difference such as vowel length or pitch can distinguish words even when a borrowed alphabet writes it poorly. Written letters are evidence about speech, but they are not speech itself.

The International Phonetic Alphabet (IPA) gives linguists a shared way to describe sounds. Square brackets such as [pʰ] indicate an observed or proposed phonetic pronunciation; slashes such as /p/ name a phoneme, an abstract contrastive unit. In historical work, neither notation is automatically a recording of an ancient speaker. A transliteration copies or represents written signs according to an editorial convention; IPA expresses a pronunciation hypothesis.

Consonants

Consonants are described by place of articulation (where the airflow is narrowed), manner (how it is narrowed) and voicing (whether the vocal folds vibrate). [p] is a voiceless bilabial stop: both lips close and release. [m] is a voiced bilabial nasal: the lips close while air exits through the nose. [s] is a voiceless alveolar fricative: the tongue approaches the ridge behind the teeth and turbulent air continues. Tap any symbol in the chart to compare the dimensions rather than memorizing letter names.

Aspiration is a burst of breath after release, transcribed [ʰ]. English pin commonly begins [pʰ] whereas spin has an unaspirated [p]; this English comparison illustrates two phonetic variants and does not establish a contrast in an ancient language.

Vowels

Vowel quality depends chiefly on tongue height, frontness or backness, and lip rounding. [i] is a high front unrounded vowel; [u] is a high back rounded vowel; [a] is low and central or front depending on the transcription system. Length is a separate dimension: [aː] is held longer than [a]. Stress, pitch and tone are likewise different properties. A historical spelling may indicate some of these reliably and leave others uncertain.