Palatal Trill

[Micamo]

I've been trying to teach myself how to do it. Right now I can do something of a alveo-palatal trill where the tongue is pressed against the hard palate, however it's still the tip of my tongue that vibrates against the alveolar ridge. This might actually be correct but I doubt it. How can I get the dorsal part of the tongue to vibrate against the palate itself?

[peterofthecorn]

I can do it, but not very comfortably or easily. Do a palatal fricative and increase the air speed until it starts to become a trill.

[Przemysław]

I can do it, but not very comfortably or easily. Do a palatal fricative and increase the air speed until it starts to become a trill.

Palatal trills don't exist. What you not very accurately describe here is a fricative trill.

One of possible variants of the Czech ⟨ř⟩ is the most „famous” fricative trill.

[peterofthecorn]

Palatal trills don't exist.

As in, they do not exist in any language, or they aren't possible to pronounce? If the latter, how do you know?

[Przemysław]

For a normal trill (and also a tap) to occur, the active articulator must be flexible, which leaves only three options:

1) the lower lip;
2) the corona;
3) the uvula.

And that's why only bilabial, coronal and uvular trills (and taps) exist. For other places, like the dorsum, vibration can occur only when an articulatory channel is constricted like in fricatives, hence the term fricative trill (and analogously fricative tap).

[Micamo]

For a normal trill (and also a tap) to occur, the active articulator must be flexible, which leaves only three options:

1) the lower lip;
2) the corona;
3) the uvula.

And that's why only bilabial, coronal and uvular trills (and taps) exist. For other places, like the dorsum, vibration can occur only when an articulatory channel is constricted like in fricatives, hence the term fricative trill (and analogously fricative tap).

Hmm, alright. I could do a palatal fricative trill all along though. But you've saved me a few hours of making weird noises!

[peterofthecorn]

For a normal trill (and also a tap) to occur, the active articulator must be flexible, which leaves only three options:

1) the lower lip;
2) the corona;
3) the uvula.

And that's why only bilabial, coronal and uvular trills (and taps) exist. For other places, like the dorsum, vibration can occur only when an articulatory channel is constricted like in fricatives, hence the term fricative trill (and analogously fricative tap).

How flexible? Because the part of the tongue that would be needed to produce a palatal trill actually is flexible, even though it is less so than the tip of the tongue. While it may be quite difficult to do, I think it is possible to produce a palatal trill.

And I think your list is incomplete: for example, the top lip is flexible, as can be shown by restraining your bottom lip and making a trill with your top lip. The sides of the tongue are flexible enough to do a lateral trill. The epiglottis, aryepiglottic fold, and vestibular fold all can also vibrate enough to make a trill.

[sangi39]

For a normal trill (and also a tap) to occur, the active articulator must be flexible, which leaves only three options:

1) the lower lip;
2) the corona;
3) the uvula.

And that's why only bilabial, coronal and uvular trills (and taps) exist. For other places, like the dorsum, vibration can occur only when an articulatory channel is constricted like in fricatives, hence the term fricative trill (and analogously fricative tap).

How flexible? Because the part of the tongue that would be needed to produce a palatal trill actually is flexible, even though it is less so than the tip of the tongue. While it may be quite difficult to do, I think it is possible to produce a palatal trill.

At least according to all copies of the IPA I've found online the palatal trill is theoretically possible but, apparently, not found in any attested language. I'd guess this results from the relatively low flexibility mentioned by Przemysław which might lead to such a sound becoming a trill at another POA (possibly palatalised) or other sounds, maybe a palatal fricative or lateral, etc.