Ankyloglossia can affect eating, speech, and oral hygiene as well as have mechanical/social effects. Ankyloglossia can also prevent the tongue from contacting the anterior palate. This can then promote an infantile swallow and hamper the progression to an adult-like swallow which can result in an open bite deformity. It can also result in mandibular prognathism; this happens when the tongue contacts the anterior portion of the mandible with exaggerated anterior thrusts.

Ankyloglossia, also known as tongue-tie, is a congenital oral anomaly that may decrease mobility of the tongue tip and is caused by an unusually short, thick lingual frenulum, a membrane connecting the underside of the tongue to the floor of the mouth. Ankyloglossia varies in degree of severity from mild cases characterized by mucous membrane bands to complete ankyloglossia whereby the tongue is tethered to the floor of the mouth.

Factors that can contribute to tongue thrusting include macroglossia (enlarged tongue), thumb sucking, large tonsils, hereditary factors, ankyloglossia (tongue tie), and certain types of artificial nipples used in feeding infants, also allergies or nasal congestion can cause the tongue to lie low in the mouth because of breathing obstruction and finally contributing to tongue thrusting. In addition, it is also seen after prolonged therapy by levodopa in Parkinsonism, also it occurs as extra pyramidal side effect (Acute muscular dystonia) after use of Neuroleptics (Anti-Psychotics).

Tongue thrust (also called reverse swallow or immature swallow) is the common name of orofacial muscular imbalance, a human behavioral pattern in which the tongue protrudes through the anterior incisors during swallowing, speech, and while the tongue is at rest. Nearly all infants exhibit a swallowing pattern involving tongue protrusion, but by six months of age most lose this reflex allowing for the ingestion of solid foods.

Since 1958, the term "tongue thrust" has been described and discussed in speech and dental publications by many writers. Many school-age children have tongue thrust. For example, according to recent literature, as many as 67–95 percent of children 5–8 years old exhibit tongue thrust, which may be associated with or contributing to an orthodontic or speech problem. Up to the age of four, there is a possibility that the child will outgrow tongue thrust. However, if the tongue thrust swallowing pattern is retained beyond that age, it may be strengthened.

OMD refers to abnormal resting posture of the orofacial musculature, atypical chewing, and swallowing patterns, dental malocclusions, blocked nasal airways, and speech problems. OMD are patterns involving oral and/orofacial musculature that interferes with normal growth, development, or function of structures, or calls attention to itself. OMD are found in both children and adults. OMD that are commonly seen in children include tongue thrust that is also known as swallowing with an anterior tongue posture. OMD also refers to factors such as nonnutritive sucking behaviors, such as thumb sucking, clenching, bruxing, etc. that led to abnormal development of dentition and oral cavity. OMD in adult and geriatric population are due to various neurological impairments, oral hygiene, altered functioning of muscles due to aging, systemic diseases, etc.

Tongue thrusting is a type of orofacial myofunctional disorder, which is defined as habitual resting or thrusting the tongue forward and/or sideways against or between the teeth while swallowing, chewing, resting, or speaking. Abnormal swallowing patterns push the upper teeth forward and away from the upper alveolar processes and cause open bites. In children, tongue thrusting is common due to immature oral behavior, narrow dental arch, prolonged upper respiratory tract infections, spaces between the teeth (diastema), muscle weakness, malocclusion, abnormal sucking habits, and open mouth posture due to structural abnormalities of genetic origin. Large tonsils and adenoids also contribute to tongue thrust swallowing.

From the dental perspective, teeth move in relation to the balance of the soft tissue; the normal relationship of teeth lies in occlusion; and any deviation from the normal occlusion can lead to dental distress. Tongue posture plays an important role in swallowing and dentofacial growth. In case of tongue thrust swallowing, the tip of the tongue can come against or between the dentition; the midpoint may be collapsed or extended unilaterally or bilaterally; or the posterior part of the hard palate. In these conditions, there are chances of abnormal dentofacial growth and other concerns regarding development of the craniofacial complex.

There are pertinent symptomatic questions that can be considered for the diagnosis of tongue thrust swallow. Some of these questions are geared toward tongue protrusion and an opening of lips when the client is in repose; habitual mouth breathing; digit sucking; existence of high and narrow palatal arch; ankyloglossia (tongue-tie); malocclusions, (Class II, III); weak chewing muscles (masseter); weak lip muscles (orbicularis oris); overdeveloped chin muscles (mentalis); muscular imbalance; abnormal dentition.

Tongue thrusting and speech problems may co-occur. Due to unconventional postures of the tongue and other articulators, interdental and frontal lisping are very common. The alveolar sounds /s/ and /z/ are produced more anteriorly thus leading to interdental fricative like sounds, /th/.

Orofacial myofunctional disorders (OMD) (sometimes called “oral myofunctional disorder", and “tongue thrust”) are muscle disorders of the face, mouth, lips, or jaw.

Recent studies on incidence and prevalence of tongue thrust behaviors are not available. However, according to the previous research, 38% of various populations have OMD. The incidence is as high as 81% in children exhibiting speech/articulation problems (Kellum, 1992).

Examples of congenital disorders which affect the tongue include:

- Aglossia - complete absence of the tongue at birth

- Ankyloglossia (tongue tie) - where the lingual frenum tethers the tongue to the floor of the mouth. If it interferes with oral hygiene and feeding, frenectomy may be indicated.

- Hypoglossia - congenitally short tongue

- Microglossia

- Macroglossia - an abnormally large tongue, seen in some disorders such as Down syndrome (although macroglossia can be an acquired condition as well).

- Hamartomata - for example Leiomyomatous hamartoma

- Glossoptosis

- Choristomata - For example, osseous choristoma of the tongue, a very rare condition characterized by a nodule on the dorsum of the tongue containing mature lamellar bone without osteoblastic or osteoclastic activity. Cartilagenous (chondroid), and glial choristomas may also very rarely occur on the tongue.

- Lingual thyroid

- Cleft tongue (bifid tongue) - completely cleft tongue is a rare condition caused by a failure of the lateral lingual swellings to merge. More common is an incompletely cleft tongue, appearing as midline fissure. This is normally classed as fissured tongue.

Successful treatments have shown that causes are functional rather than physical: that is, most lisps are caused by errors in tongue placement within the mouth rather than caused by any injury or congenital deformity to the mouth. The most frequently discussed of these problems is tongue thrust in which the tongue protrudes beyond the front teeth. This protrusion affects speech as well as swallowing and can lead to lisping. Ankyloglossia or tongue tie can also be responsible for lisps in children.

However, it is unclear whether these deficiencies are caused by the tongue tie itself or the muscle weakness following the correction of the tongue tie. Overbites and underbites may also contribute to non lingual lisping. Temporary lisps can be caused by dental work, dental appliances such as dentures or retainers or by swollen or bruised tongues.

A lisp, also known as sigmatism, is a speech impediment in which a person misarticulates sibilants (, , , ), (, , , ). These misarticulations often result in unclear speech.

Clinical diagnosis based on orofacial clefts and lip pits typically occurs shortly after birth. Certain defects may be difficult to diagnose, particularly a submucous cleft palate. This form of CP may not be detected except through finger palpation, as the mucosa covering the palate is intact, but the muscles underneath have lost their proper attachments. Feeding problems, impaired speech, and hearing loss are symptoms of a submucous cleft palate. Furthermore, approximately 15% of VWS cases with orofacial clefts, in the absence of prominent lip pits, cannot be easily distinguished from non-syndromic forms of orofacial clefting. Therefore, it is very important to closely examine these patients as well as their relatives for lip pits, especially when there is a family history of mixed clefting, in order to make the VWS diagnosis. Dentists may also play an important role in diagnosing cases not detected at birth, as they detect hypodontia commonly associated with VWS. The

patients most commonly lack the upper second premolars followed by the lower second premolars and upper lateral incisors. The absence of these teeth might play a role in the constricting of the dental arches.

The clinical signs seen in VWS are similar to those of popliteal pterygium syndrome (PPS), which is also an autosomal dominant disease. Approximately 46% of affected individuals have lip pits; other features include genital abnormalities, abnormal skin near nails, syndactyly of fingers and toes, and webbed skin. The disease is also caused by mutations in "IRF6"; however, they occur in the DNA-binding domain of "IRF6" and result in a dominant negative effect in which the mutated IRF6 transcription factor interferes with the ability of the wild type copy to function, in the case of a heterozygous individual.

Tongue diseases can be congenital or acquired, and are multiple in number. Considered according to a surgical sieve, some example conditions which can involve the tongue are discussed below. Glossitis is a general term for tongue inflammation, which can have various etiologies, e.g. infection.

Van der Woude syndrome (VDWS) is a genetic disorder characterized by the combination of lower lip pits, cleft lip with or without cleft palate, and cleft palate alone (CP). The frequency of orofacial clefts ranges from 1:1000 to 1:500 births worldwide, and there are more than 400 syndromes that involve cleft lip with or without cleft palate. VWS is distinct from other clefting syndromes due to the combination of cleft lip and palate (CLP) and CP within the same family. Other features frequently associated with VWS include hypodontia in 10-81% of cases, narrow arched palate, congenital heart disease, heart murmur and cerebral abnormalities, syndactyly of the hands, polythelia, ankyloglossia, and adhesions between the upper and lower gum pads.

The association between lower lip pits and cleft lip and/or palate was first described by Anne Van der Woude in 1954. The worldwide disease incidence ranges from 1:100,000 to 1:40,000.