Messner "et al." studied ankyloglossia and infant feeding. Thirty-six infants with ankyloglossia were compared to a control group without ankyloglossia. The two groups were followed for six months to assess possible breastfeeding difficulties; defined as nipple pain lasting more than six weeks, or infant difficulty latching onto or staying onto the mother’s breast. Twenty-five percent of mothers of infants with ankyloglossia reported breastfeeding difficulty compared with only 3% of the mothers in the control group. The study concluded that ankyloglossia can adversely affect breastfeeding in certain infants. Infants with ankyologlossia do not, however, have such big difficulties when feeding from a bottle. Limitations of this study include the small sample size and the fact that the quality of the mother’s breastfeeding was not assessed.

Wallace and Clark also studied breastfeeding difficulties in infants with ankyloglossia. They followed 10 infants with ankyloglossia who underwent surgical tongue tie division. Eight of the ten mothers experienced poor infant latching onto the breast, 6/10 experienced sore nipples and 5/10 experienced continual feeding cycles; 3/10 mothers were exclusively breastfeeding. Following a tongue-tie division, 4/10 mothers noted immediate improvements in breastfeeding, 3/10 mothers did not notice any improvements and 6/10 mothers continued breastfeeding for at least four months after the surgery. The study concluded that tongue-tie division may be a possible benefit for infants experiencing breastfeeding difficulties due to ankyloglossia and further investigation is warranted. The limitations of this study include the small sample size and the fact that there was not a control group. In addition, the conclusions were based on subjective parent report as opposed to objective measures.

Opinion varies regarding how frequently ankyloglossia truly causes problems. Some professionals believe it is rarely symptomatic, whereas others believe it is associated with a variety of problems. The disagreement among professionals was documented in a study by Messner and Lalakea (2000). The authors sent a survey to a total of 1598 otolaryngologists, pediatricians, speech-language pathologists and lactation consultants with questions to ascertain their beliefs on ankyloglossia. 797 of the surveys were fully completed and used in the study. It was found that 69% of lactation consultants, but only a minority of pediatricians answered that ankyloglossia is frequently associated with feeding difficulties; 60% of otolaryngologists and 50% of speech pathologists answered that ankyloglossia is sometimes associated with speech difficulties compared to only 23% of pediatricians; 67% of otolaryngologists compared with 21% of pediatricians answered that ankyloglossia is sometimes associated with social and mechanical difficulties. Limitations of this study include a reduced sample size due to unreturned or incomplete surveys.

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 is normal in infants until approximately the age of six months. The loss of this normal infant behavior is one of the signs that the baby is ready to begin eating baby food.

Tongue thrusting can adversely affect the teeth and mouth. A person swallows from 1,200 to 2,000 times every 24 hours with about four pounds (1.8 kg) of pressure each time. If a person suffers from tongue thrusting, this continuous pressure tends to force the teeth out of alignment. Many people who tongue thrust have open bites; the force of the tongue against the teeth is an important factor in contributing to "bad bite" (malocclusion). Many orthodontists have completed dental treatment with what appeared to be good results, only to discover that the case relapsed because of the patient's tongue thrust. If the tongue is allowed to continue its pushing action against the teeth, it will continue to push the teeth forward and reverse the orthodontic work.

Speech is not frequently affected by the tongue thrust swallowing pattern. The "S" sound (lisping) is the one most affected. The lateral lisp (air forced on the side of the tongue rather than forward) shows dramatic improvement when the tongue thrust is corrected. However, lisping and tongue thrust are not always associated.

The adaptation from nasal to mouth breathing takes pace when changes such as chronic middle ear infections, sinusitis, allergic rhinitis, upper airway infections, and sleep disturbances (e.g., snoring) take place. In addition, mouth breathing is often associated with a decrease in oxygen intake into the lungs. Mouth breathing can particularly affect the growing face, as the abnormal pull of these muscle groups on facial bones slowly deforms these bones, causing misalignment. The earlier in life these changes take place, the greater the alterations in facial growth, and ultimately an open mouth posture is created where the upper lip is raised and the lower jaw is maintained in an open posture. The tongue, which is normally tucked under the roof of the mouth, drops to the floor of the mouth and protrudes to allow a greater volume of air intake. Consequently, an open mouth posture can lead to malocclusions and problems in swallowing. Other causes of open-mouth posture are weakness of lip muscles, overall lack of tone in the body or hypotonia, and prolonged/chronic allergies of the respiratory tract. A.union

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).

Genetic counseling for VWS involves discussion of disease transmission in the autosomal dominant manner and possibilities for penetrance and expression in offspring. Autosomal dominance means affected parents have a 50% chance of passing on their mutated "IRF6" allele to a their child. Furthermore, if a cleft patient has lip pits, he or she has a ten times greater risk of having a child with cleft lip with or without cleft palate than a cleft patient who does not have lip pits. Types of clefting between parents and affected children are significantly associated; however, different types of clefts may occur horizontally and vertically within the same pedigree. In cases where clefting is the only symptom, a complete family history must be taken to ensure the patient does not have non-syndromic clefting.

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.

Tongue lesions are very common. For example, in the United States one estimated point prevalence was 15.5% in adults. Tongue lesions are more common in persons who wear dentures and tobacco users. The most common tongue conditions are geographic tongue, followed by fissured tongue and hairy tongue.

Lip pits may be surgically removed either for aesthetic reasons or discomfort due to inflammation caused by bacterial infections or chronic saliva excretion, though spontaneous shrinkage of the lip pits has occurred in some rare cases. Chronic inflammation has also been reported to cause squamous-cell carcinoma. It is essential to completely remove the entire lip pit canal, as mucoid cysts can develop if mucous glands are not removed. A possible side effect of removing the lip pits is a loose lip muscle. Other conditions associated with VWS, including CL, CP, congenital heart defects, etc. are surgically corrected or otherwise treated as they would be if they were non-syndromic.

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

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.