Speech is a privileged means of communication for humans: its trouble can thus prove being extremely handicapping. Standard speech therapy is limited in some cases by the lack of sensory feedback available to the patient (hearing, surgery, neural damage, etc.).

The present study aims at quantify the contribution of the tongue articulatory visual feedback offered by ultrasound echography to speech trouble rehabilitation.

Two complementary populations will be studied : 30 adults with buccopharyngeal surgery, and 10 childrens with important speech troubles due to central nervous system damage.

The principle is to conduct standard speech therapy sessions, alternating series of sessions with the use of visual feedback and sessions without visual feedback.

The progress will be regularly measured by means of standard batteries of speech articulation tests.

Inclusion Criteria:

• Articulatory troubles needing speech therapy
• French mother tongue
• Adult patients [18 ≥ age < 80 years] who underwent buccopharyngeal surgery after cancer diagnostic OR children [8 ≥ age < 18 years] suffering from central nervous system damage

Exclusion Criteria:

• Incapacity to easily understand the speech therapist instructions
• People protected by the law
• People deprived from freedom by judiciary decision
• Potential allergy to the water-based conducting gel used to ensure good skin - probe contact
• Overweight if large fatty mass under chin
• Major edema under chin limiting echogenicity
• Non corrected vision or hearing problems
• For the adults: central or peripheral neural damage
• History of Ear, Nose, and Throat surgery or radiotherapy
• For the adults: isolated articulatory trouble, former articulatory trouble not treated, disfluency
• Massive orofacial dyspraxia
• Posture trouble
• Motor problem in upper limbs