In phonetics, denasalization is the loss of nasal airflow in a nasal sound. That may be due to speech pathology but also occurs when the sinuses are blocked from a common cold, when it is called a nasal voice, which is not a linguistic term. Acoustically, it is the "absence of the expected nasal resonance." The symbol in the Extended IPA is ⟨◌͊⟩. When one speaks with a cold, the nasal passages still function as a resonant cavity so a denasalized nasal does not sound like a voiced oral stop, and a denasalized vowel does not sound like an oral vowel. However, there are cases of historical or allophonic denasalization that have produced oral stops. In some languages with nasal vowels, such as Paicĩ, nasal consonants may occur only before nasal vowels; before oral vowels, prenasalized stops are found. That allophonic variation is likely to be from a historical process of partial denasalization. Similarly, several languages around Puget Sound underwent a process of denasalization about 100 years ago. Except in special speech registers, such as baby talk, the nasals became the voiced stops. It appears from historical records that there was an intermediate stage in which the stops were prenasalized stops or poststopped nasals. Something similar has occurred with word-initial nasals in Korean; in some contexts, are denasalized to. The process is sometimes represented with the IPA and, which simply places the IPA denasalization diacritic on and to show the underlying phoneme. In speech pathology, practice varies in whether ⟨m͊⟩ is a partially denasalized, with ⟨b⟩ for full denasalization, or is a target whether it is partially denasalized or a fully denasalized.