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Prosody comprises patterns of pitch, timing and emphasis extending across the individual segments of speech. Speech intonation concerns the changing pitch pattern, while speech rhythm concerns the temporal organization. The same sequence of words can be spoken with different prosody.

For acoustic analysis, a recording is examined over time. A spectrogram can reveal changes in the fundamental frequency of voiced portions; segment durations and pauses provide timing measurements. The perceived pitch and emphasis are perceptual judgments, so they should be distinguished from the measured frequency and sound pressure. Phonetics relates the recorded signal to its production and perception.

Speech rhythm is the temporal organization of speech: the durations and grouping of segments, syllables, pauses and prominent portions of an utterance. It is one component of prosody, distinct from the changing pitch pattern of speech intonation.

An original measurement exercise is to record several repetitions of a short phrase at a comfortable rate, then again more quickly. Mark the same chosen boundaries on each recording and compare the elapsed times between them. Normalizing an interval by the utterance's total duration distinguishes uniform speeding-up from redistribution of time within the phrase. The result depends on which boundaries were marked, so the annotation rule is part of the measurement method. Software such as Praat stores labelled time intervals in separate annotation tiers, allowing the audio and its proposed segmentation to be inspected together.^[ref]

Perceived rhythmic prominence is not simply the height of the sound pressure waveform. Duration, pitch and intensity can contribute differently, and a claim about regular timing requires measured intervals rather than an impression of a beat.

A syllable organizes speech sounds around a syllable nucleus, often a vowel. A preceding syllable onset and a following syllable coda can surround that nucleus. These components describe the organization of speech, rather than a requirement to pause between successive units.^[ref]

For example, in a simple pronunciation of “cat”, [k] occupies the onset, [æ] the nucleus and [t] the coda. A syllable can have an empty onset or coda, so the example's three-part form is not a mandatory template for every word. A syllabic consonant can also serve as a nucleus.

The distinction matters in speech rhythm: counting letters, counting phonemes and identifying syllables are different operations. Physical measurements of duration and pitch contours can be related to syllable organization, but they do not imply a silent gap at every proposed boundary.