Linguograms

When all the required pictures of the roof of the mouth have been obtained, the procedure can be reversed to produce linguograms, which are simply records of the areas of the tongue that have come in contact with the roof of the mouth.

• Paint the upper surface of the mouth with the same mixture described in the palatography section.
• Have the speaker produce the desired sound and observe (and photograph) the part of the tongue that is making the contact.

9 It may be necessary to instruct the speaker to move the tongue up, down or to the side, to show sublaminal contact, or contact on the sides of the tongue.

• Once you have finished taking the pictures, have the speaker rinse out their mouths with lemonade or lemon juice.

NOTE: Speakers' tongues differ in their absorbency to the charcoal mixture.  For speakers whose tongues begin to collect black color despite repeated rinsings, it is preferable to begin by painting the roof of the mouth and obtaining the linguograms first, since repeatedly painting the tongue can cause loss of contrast. 

Fig 3:  Linguogram showing tongue blade and body contact.	Fig 4:  Linguogram showing tongue tip contact and sublaminal contact (contact under the tongue.)

NOTE: In both photographs, the black contact areas reflect the SUM of the articulatory contacts that occurred in the pronunciation of the word investigated. They do not show the tongue’s position at any one particular moment.  In addition, the photographs of the tongue usually show it when it has been slightly stuck out of the mouth, and is therefore not in the same shape as it was when producing any of the sounds.