Dental and labiodental fricatives with different relative positions of the articulators

Question

Are there distinct phonemes for labiodental fricatives articulated with the upper teeth touching the lower lip from the inside (like in English /f/) and ones that are articulated with the tip of the upper teeth placed on the lower lip (like biting your lip only gentler)?

Likewise for dental fricatives between phonemes articulated with the tip of the tongue touching the teeth (like in English /θ/ ) and one articulated with the front of the tongue between the teeth (like biting tour tongue)? And for the tip of the tongue pressed against the upper teeth?

For all these are the distinct phonetic symbols or are they just represented by the symbols for the standard positions marked with diacritics (like θ̟ and θ̝)?

Answer 1

Such contrasts are not attested in any known language. In the case of the two kinds of labiodentals, the distinction would be auditorily unlearnable since the acoustic consequences are negligible. However, dental versus interdental non-sibilant fricatives have been observed, but never found to contrast. Ladefoged & Maddieson The sounds of the world's languages mention Spanish vs. Tamil as examples of interdental vs. dental fricatives, and California English vs. UK English as illustrating the same difference.

There will not be a distinction in symbols until the difference is shown to be phonemic in some languages; until then, you can use diacritics (and even then, it has to be officially proposed and voted on).