> (1) When can we anticipate that the USE spec will be updated to provide
> support for subjoined consonants below vowels (as required for TAI THAM) ?
• The exact scope is actually about allowing conjoined consonant forms (either
encoded with a stacker, or encoded atomically?) after vowel signs in an encoded
cluster.
> ** A good use case is the Tai Tham word U+1A27 U+1A6A U+1A60 U+1A37 ,
> transcribed to Central Thai script as จูบ, (to kiss). Currently, people are
> writing this as U+1A27 U+1A60 U+1A37 U+1A6A ("จบู") which violates the
> "phonetic ordering" but is the current workaround because USE is still broken
> for TAI THAM.
• I agree with Richard on that this is really not a good use case. This word
(as long as it is written with the vowel sign Uu either under or after the
conjoined consonant sign B) should really be encoded as <High Ca, stacker, Ba,
sign Uu>, according to our best understanding today.
• The “phonetic ordering” principle of Unicode is a frequently misinterpreted
one. Note that when there are multiple ways of interpreting the phonetic order
of a written structure, we try to stick to the more graphically apparent order,
in order to have a stable encoding order.
> An example of the contrast is shown in the attached files luynam.png, with
> first orthographic syllable <LA, SIGN U, SAKOT, LOW YA>, and yukya.png, with
> the first orthographic syllable <HIGH HA, SAKOT, LOW YA, SIGN U>.
• Right. I was always wondering to what extent this distinction happens as an
orthographically conscious choice.
• Generally I feel, when at least one of the interacting signs (usually a
consonant one and a vowel one) has inline advance, it should be safe to take a
graphic order approach. The “6th preliminary recommendation” doesn’t have the
luynam vs yukya case taken into consideration mostly only because we wasn’t
sure about what good attestations are there.
> * Create new SAKOT class SAKOT (Sk) based on UISC = Invisible_Stacker
> * Reduced HALANT class Now only HALANT (H) based on UISC = Virama
• This feels like an undesirable Tham-specific relaxation. Note the artificial
distinction between UISC Invisible_Stacker and Virama has nothing to do with
whether graphically writing a consonant sign after a vowel sign is attested for
a script. (কা)
• At least we need to look into USE-applicable (existing and future) scripts
encoded with a Virama and see if any of them does need the relaxation.
> * Updated Standard cluster mode [< R | CS >] < B | GB > [VS] (CMAbv)*
> (CMBlw)* (< < H | Sk > B | SUB > [VS] (CMAbv)* (CMBlw)) [MPre] [MAbv] [MBlw]
> [MPst] (VPre)* (VAbv)* (VBlw)* (VPst)* (VMPre)* (VMAbv)* (VMBlw)* (VMPst)*
> (Sk B)* (FAbv)* (FBlw)* (FPst)* [FM]
• I’m still trying to think about the possibility of only relaxing the cluster
when either/both of <vowel sign, consonant sign> has post-base advance…
• The artificial distinction made between < H | Sk > B, SUB, and CM really
needs to be resolved together with the relaxation.
> * Updated Halant-terminated cluster [< R | CS >] < B | GB > [VS] (CMAbv)*
> (CMBlw)* (< < H | Sk > B | SUB > [VS] (CMAbv)* (CMBlw)) < H | Sk >
• So, the intention of allowing Sk at the end is only about allowing the glyph
of Sk to be positioned on the preceding character(s), right?
> * New Sakot-terminated cluster [< R | CS >] < B | GB > [VS] (CMAbv)* (CMBlw)*
> (< < H | Sk > B | SUB > [VS] (CMAbv)* (CMBlw)) [MPre] [MAbv] [MBlw] [MPst]
> (VPre)* (VAbv)* (VBlw)* (VPst)* (VMPre)* (VMAbv)* (VMBlw)* (VMPst)* (Sk B
> [VS] (CMAbv)* (CMBlw)) Sk
• The “(Sk B [VS] (CMAbv)* (CMBlw)) Sk” part doesn’t seem to align with the
updated Standard cluster’s “(Sk B)*”?
> I trust you'll be reclassifying U+1A55 TAI THAM CONSONANT SIGN MEDIAL RA and
> U+1A56 TAI THAM CONSONANT SIGN MEDIAL LA into the category SUB so that we can
> write about bananas forever (ᨠᩖ᩠ᩅ᩠᩶ᨿᨲᩕ᩠ᩃᩬᨯ): <HIGH KA, MEDIAL LA, SAKOT, WA,
> TONE-2, SAKOT, LOW YA> /kluai/ 'banana' <HIGH TA, MEDIAL RA, SAKOT, LA, SIGN
> OA BELOW, DA> /tʰalɔːt/ 'for ever' The issues here are that WA in a medial
> rôle is indistinguishable from a coda ('sakot') consonant and that MEDIAL RA
> can act as a consonant aspirator.
• The issues here are:
• Medial consonant sign characters of Tham are not encoded based on a
clear phono-orthographical distinction.
• Tham allows syllable chaining that does not rely on a preceding
inline coda letter.
• Consonant sign Medial Ra being a consonant aspirator here is not relevant to
its appearance before a non-medial consonant sign here.
Best,
梁海 Liang Hai
https://lianghai.github.io
