Why can removing adenoids sometimes worsen hypernasal speech?

Removing adenoids can worsen hypernasal speech when a patient has underlying palatal incompetence, such as a slight congenital malformation or palate paresis.1

In some cases, a patient may have "mixed nasality," where the adenoids are obstructing the nasopharynx—causing hyponasal (closed) speech—while the palate is simultaneously unable to close off the nasal cavity properly during speech, causing an underlying open (hypernasal) component.1

When the adenoids are removed to alleviate airway obstruction or middle-ear issues, the physical barrier that was helping to seal the nasopharynx is lost. While this successfully treats the closed nasality, it exposes the previously masked palatal incompetence. Consequently, the open nasality becomes more severe, leading to a marked deterioration in the patient’s speech. Because of this risk, a complete evaluation by an otolaryngologist or phoniatrist is essential before performing an adenoid operation to ensure that the benefits to health and hearing are carefully weighed against the potential for worsened speech.1