## 3 Effects of Malocclusion on Speech
### Anterior-Posterior Discrepancies
_Class II_: Class II malocclusions have been linked to distorted speech, but Class II DFD patients have received less attention in the speech literature, despite Class II malocclusions constituting a majority of orthodontic patients [44; 77]. This dearth of studies may be due to the smaller spectral shifts associated with fewer sounds among Class II patients compared with other DFD cohorts [44]. Class II patients can temporarily posture their lower jaw anteriorly into a normal Class I position (\"Sunday bite\"): a compensatory movement that is not possible with Class III and AOB DFD groups (as patients cannot voluntarily move their maxilla or retract their mandible without surgery) [78]. Compensation may \begin{table}
\begin{tabular}{c c} \hline \hline
**Distortion** & **Description** \\ \hline Auditory distortion & Sound produced is perceived as aberrant but may look acceptable to the listener. \\ \hline Visual distortion & Sound is perceived as correct but looks abnormal to the listener. Example: Speaker who produces a bilabial sound /p,b,m/ by placing the lower lip against the upper incisors. Consonant sounds normal but looks incorrect. \\ \hline \multirow{4}{*}{Lisp} & A type of functional speech disorder: usually a phonetic disorder, meaning the affected person struggles to correctly position the tongue, lips, teeth, and jaw to achieve the attempted sound. Lisps are the most commonly identified and widely recognized speech problem. A “lisp” is an articulation problem that results in the ability to pronounce one or more consonants. There are 4 main types of lips (inderdental, dentalized, lateral, and palatal). Some lipss are common and normal at various stages in development but should fade as children age. Lisps can be treated by an SLP with speech therapy. \\ \hline \multirow{4}{*}{Interdental lisp} & Most common and well-known type of lisp, which is due to incorrect placement of the tongue within the mouth, with the tongue pushing forward between the front teeth. Most common is the inability to pronounce the sibilants /s/ or /z/, with production sounding like “th”. Called frontal distortion type I by [PERSON] and [PERSON] (1993) [48]. \\ \hline \multirow{4}{*}{Dentalized lisp or detnalized production} & The tongue tip pushes against the upper or lower anterior teeth (incisors), resulting in a muffled /s/ or /z/ sound. The tongue body is flattened, causing scattering of the air stream. Called frontal distortion type II by [PERSON] and [PERSON] (1993) [48]. \\ \hline \multirow{4}{*}{Lateralized lisp} & The air stream is diverted to one or both sides of the tongue, with air exiting the mouth out of the sides. This results in slushy or wet sounding speech, as speech is mixed with the sound of air mixing with saliva. Examples: [PERSON] or \\  & Sylvester the Cat. \\ \hline \multirow{2}{*}{Palatal lisp} & Least common type of lisp. Occurs when the center of tongue is in contact with the hard or soft palate, when attempting to produce the /s/ sound. \\ \hline \multirow{2}{*}{Whistling} & High-frequency sound created by air passing between the tongue and \\  & alveolar ridge \\ \hline \multirow{2}{*}{Labiodentalization} & Lower lip contacts the maxillary incisors \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Glossary of terms describing articulation errors associated with DFD. help Class II patients approximate normal [s] and [z] articulation [48]. In some cases, attempting compensatory articulation contributes to distortions, with the protrusion of the tongue past the incisors (\"interdental lisping\") during the production of /s/, leading to an audible lisp [48; 50]. Perceptually, this imprecise articulation of siblants [s] and [z] can be attributed to a reduced oral opening caused by the deep bite seen in many Class II patients [72; 75].