Debuccalization or deoralization[1] is a sound change or alternation in which an oral consonant loses its original place of articulation and moves it to the glottis ([h], [ɦ], or [ʔ]).
Debuccalization is usually seen as a subtype of lenition, which is often defined as a sound change involving the weakening of a consonant by progressive shifts in pronunciation.
As with other forms of lenition, debuccalization may be synchronic or diachronic (i.e. it may involve alternations within a language depending on context or sound changes across time).
However, Standard German spoken in Luxembourg often lacks syllabic sonorants under the influence of Luxembourgish, so that -en is pronounced [ən], rather than [n̩] or [ŋ̍].
[7] In every Gorontalic language except Buol and Kaidipang, *k was replaced by a glottal stop, and lost altogether in word-initial position: *kayu → Gorontalo ayu 'wood', *konuku → olu'u 'fingernail'.
In Talaud, all instances of Proto-Sangiric *k were debuccalized into ʔ except when following *ŋ (*kiki → i'i "to bite", but *beŋkol → bengkola "bent").
Other newer instances of k resulted from *R when geminated or being word-final (ʐ elsewhere), e.g. *bəRu → bakku "new", *bibiR → biwikka "lip", *bəŋaR → bangngaka "molar".
In some varieties of Scots and Scottish English, particularly on the West Coast, a non word-final /θ/ th shifted to [h], a process called th-debuccalization.
Additionally, the Proto-Indo-European aspirated voiced palato-velar *ǵʰ [ɟʱ] became [ɦ] through successive affrication, assibilation and debuccalization: e.g. *bʰeh₂ǵʰús "arm" becomes Sanskrit bāhúḥ.
In many Eastern Bengali dialects, the voiceless palato-alveolar sibilant /ʃ/ can become debuccalized to glottal [h] or [ɦ], e.g. /ʃälä/ "wife's brother" is [ɦälä], and /ʃägoɾ/ "sea" is [ɦä(g)oɾ].
In many varieties of Galician, as well as in Galician-influenced Spanish, the phoneme /ɡ/ may debuccalize (gheada) to [ħ] in most or all instances; [x] and [h] are also possible realizations.
There is also an inverse hypercorrection process of older or less educated Galician speakers replacing the phoneme /x/ of the Spanish language with [ɡ], which is called gueada.
Throughout Brazil, the phoneme /ʁ/ (historically an alveolar trill /r/ that moved to an uvular position) has a rather long inventory of allophones: [r ɻ̝̊ ç x ɣ χ ʁ ʀ ħ h ɦ].
However, in some mineiro- and mineiro-influenced fluminense rural registers, [h] is used but as an allophone of /l/ (rhotic consonants are most often deleted), a mar-mal merger, instead of the much more common and less-stigmatized mau-mal merger characteristic of all Brazilian urban centers except for those bordering Mercosur countries, where coda [ɫ] was preserved, and the entire North and Northeast regions.
Its origin is the replacement of indigenous languages and línguas gerais by Portuguese,[citation needed] which created [ɹ], [ɻ] and r-colored vowel as allophones of both /ɾ/ (now mostly /ʁ/) and /l/ (now mostly [u̯ ~ ʊ̯]) phonemes in the coda since Native Brazilians could not easily pronounce them (caipira dialect).
[citation needed] The later Portuguese influence from other regions made those allophones become rarer in some areas, but the mar-mal merger remained in a few isolated villages and towns.