- Sagittal section
- SAMPA
- Sandhi
- Sawtooth wave
- Scala
- Schwa
- Secondary articulation
- Semivowel
- Sensorineural hearing loss
- Sentence stress
- Series
- Sharp
- Sibilant
- Sine wave
- Sinusoid
- Slender consonant
- Slit fricative
- Sociolect
- Soft consonant
- Soft palate
- Sonagram
- Sonagraph
- Sonorant
- Sonority hierarchy
- Southern breaking
- Spectrogram
- Spectrograph
- Spectrum
- Speech pressure waveform
- Speech reading
- Speech synthesis
- Spelling pronunciation
- Spirantisation
- Split
- Spoonerism
- Square wave
- Stapes
- Starred form
- Steady state
- Stirrup
- Stød
- Stop
- Stopping
- Stranding
- Stress
- Stress clash
- Stress shift
- Stress-timed
- Stretching
- Strict Layer Hypothesis
- Stricture
- Strident
- Strong cluster
- Strong form
- Suppletion
- Surd
- Surface form
- Svarabhakti
- Syllabary
- Syllabic consonant
- Syllable
- Syllable nucleus
- Syllable-timed
- Syllable weight
- Syncope
- Synizesis
- Syntactic doubling
- Systematic gap
- Systemic difference