The consonant phonemes of Fox are given in the table below. There are twelve vowel phonemes: short /a, e, i, ɒ, o, u/ and long /aː, eː, iː, ɒː, oː, uː/.
The orthography with the letter y is pronunciation /ɒ/.
| Labial | Alveolar | Postalveolar or palatal |
Velar | Glottal | ||
|---|---|---|---|---|---|---|
| Nasal | m | n | ɲ | ŋ | ||
| Stop | voiced | b | d | l /dʒ/ | ɡ | |
| plain | p | t | c /tʃ/ | k | ||
| preaspirated | ʰp | ʰt | ʰtʃ | ʰk | ||
| Fricative | voiceless | s | f /ʃ/ | h | ||
| voiced | z | v /ʒ/ | ||||
| Approximant | r /ɹ/ | j | w | |||
Other than those involving a consonant plus /j/ or /w/, the only possible consonant cluster is /ʃk/.
Until the early 1900s, Fox was a phonologically very conservative language and preserved many features of Proto-Algonquian; records from the decades immediately following 1900 are particularly useful to Algonquianists for this reason. By the 1960s, however, an extensive progression of phonological changes had taken place, resulting in the loss of intervocalic semivowels and certain other features.