In historical linguistics and language contact, unpacking is the separation of the features of a segment into distinct segments.

Perhaps the most common example of unpacking is the separation of nasal vowels into vowel plus nasal consonant when borrowed into languages which don't have nasal vowels. This can be seen in English borrowings of French and Portuguese words, such as monsoon [mɒnˈsuːn] from Portuguese monção [mõsɐ̃ũ], but occurs widely, as in Lingala [balansi] from French [balɑ̃s] "balance". Here the nasality of the vowel is separated out as a nasal consonant. If this did not happen, the nasality would be lost.

Unpacking occurs not just in borrowings, but within a language over time. For example, Armenian changed the Proto-Indo European syllabic resonants *m̥, *n̥, *r̥, and *l̥ into am, an, ar, and al, keeping the syllabic nature of the sound while preserving the consonant value. Thus, the privative prefix *n̥- has changed into ան- an-, and the word *mr̥tos has become մարդ mard.

See also