interdentaalinen
Interdentaalinen is a linguistic term used to describe a place of articulation in which the tongue blade or tip is positioned between the upper and lower teeth. In English and many analyses, the primary interdental sounds are the voiceless fricative represented by theta, /θ/, as in think, and the voiced fricative represented by eth, /ð/, as in this. These sounds are produced with the airflow directed between the teeth, often with the tongue touching or close to the teeth.
The articulation is often described as between dental and alveolar, and some researchers distinguish true interdental
Orthography historically associates interdental sounds with the letters thorn (Þ, þ) and eth (Ð, ð) from Old
In summary, interdentaalinen refers to sounds produced with the tongue between the teeth, most notably the /θ/