In historical linguistics

Historical linguistics

Historical linguistics is the study of language change. It has five main concerns:* to describe and account for observed changes in particular languages...

 and language contact

Language contact

Language contact occurs when two or more languages or varieties interact. The study of language contact is called contact linguistics.Multilingualism has likely been common throughout much of human history, and today most people in the world are multilingual...

, unpacking is the separation of the features

Distinctive feature

In linguistics, a distinctive feature is the most basic unit of phonological structure that may be analyzed in phonological theory.Distinctive features are grouped into categories according to the natural classes of segments they describe: major class features, laryngeal features, manner features,...

 of a segment

Segment (linguistics)

In linguistics , the term segment may be defined as "any discrete unit that can be identified, either physically or auditorily, in the stream of speech."- Classifying speech units :...

 into distinct segments.

Perhaps the most common example of unpacking is the separation of nasal vowel

Nasal vowel

A nasal vowel is a vowel that is produced with a lowering of the velum so that air escapes both through nose as well as the mouth. By contrast, oral vowels are ordinary vowels without this nasalisation...

s 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 didn't happen the nasality would be lost.

Consonants may also be unpacked. Basque

Basque language

Basque is the ancestral language of the Basque people, who inhabit the Basque Country, a region spanning an area in northeastern Spain and southwestern France. It is spoken by 25.7% of Basques in all territories...

 unpacks palatal consonant

Palatal consonant

Palatal consonants are consonants articulated with the body of the tongue raised against the hard palate...

s in Spanish loans, so that for instance baño [baɲo] "bath" appears as bainu [bainu]. Here the palatal feature of the consonant separates out as the palatal vowel [i].

Unpacking occurs not just in borrowings, but within a language over time. Sanskrit

Sanskrit

Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...

 syllabic ऋ [r̩] has become [ɾɪ] in Hindi, which has no syllabic consonant

Syllabic consonant

A syllabic consonant is a consonant which either forms a syllable on its own, or is the nucleus of a syllable. The diacritic for this in the International Phonetic Alphabet is the under-stroke, ⟨⟩...

s; the rhotic

Rhotic

In linguistics, rhotic can refer to:* Rhotic consonant, such as the sound in red* R-colored vowel, such as the sound in Midwestern American English pronunciation of fur and before a consonant as in hard....

ity is maintained by the [ɾ], while the syllabic feature is separated out as a vowel.