Defective _articulation_ is another serious accompaniment of these deformities. Although this may be present to a slight degree as a result of a simple cleft in the lip, yet it is only when the palate is imperfect that the trouble is obviously manifest. The defect consists in the inability to articulate distinctly any but the open vowel sounds, and those few consonants which do not require the nasal cavity to be entirely shut off from the buccal. For the production of the labials, dentals, and gutturals, it is essential that there be a complete closure of the posterior nares; and as the mechanism for effecting this is imperfect, the production of the sounds must be similarly defective. In spite of these difficulties, it is extraordinary how adults suffering in this way can by practice make themselves understood. This inability to completely shut off the nose from the mouth is undoubtedly the primary cause of the nasal twang imparted to the voice. Even a small aperture is sufficient to give rise to a marked defect in speech; whilst cases are recorded where without any actual cleft the velum from deficient antero-posterior length could not be approximated to the posterior pharyngeal wall, and a similar condition of speech has resulted. Indeed, in many instances where a scanty palate has been successfully sutured, the cacophonic sounds may for a time persist, though to a less degree than before the operation, a result either of inability to make this contact through an uncorrected faulty habit or tension of the velum, or due to the presence of some small opening. The peculiarity of the twang imparted to the voice varies according to the amount of communication between the mouth and nose, the size of the nasal cavities, and the shape of the nostril aperture. Where the tonsils are enlarged, and adenoid vegetations exist in considerable numbers on the pharyngeal wall, the size of the communication may be reduced, and articulation thus rendered more distinct. It is a question, therefore, whether these growths should be removed unless for some pressing reason. Singing is interfered with, though to a much less degree than is ordinary speech, although the words sung will be indistinct. Whispering, moreover, is impossible; but most of these conditions will not be very manifest if the velum alone be fissured. Mason notes that it is very difficult, and in some cases impossible, for the patients to blow out a candle; and similarly they cannot perform on wind instruments.