[OpenType] Language System Tags for Embera languages and Pilaga

[moyogo]

At least two Emberá languages, Northern Emberá [emp], Emberá Chamí [cmi], use the letters B with a median stroke and D with a median stroke in some orthographies, and Pilagá [plg] uses the letter B with a media stroke.
There is already a recently encoded Ꟈ U+A7C7 and ꟈ U+A7C8 that may be used instead of Đ U+0110 and đ U+0111, but there is no specific character for B with median stroke, if or Ƀ U+0243 and ƀ U+0180 or Đ U+0110 and đ U+0111 or Ƀ U+0243 and ƀ U+0180 are used their shapes in these two Emberá languages should be different than their default shape in pretty much all modern fonts which have a short stroke on the bottom right or bottom right of the capitals and through the ascender of the small letters, whereas the letters in Emberá orthographies have a long stroke or even a diagonal stroke through the capitals B and D and a median stroke through the small letters b and d and the letters in Pilagá orthogaphy have a long stroke through the capital B and a median stroke through the small letter b.

The Language System Tag 'PLG ' is already defined for "Palaung", Pilagá could use 'PLG0'.

Please consider adding the following Language System Tags:

Language System	Language System Tag	Corresponding ISO 639 ID (if applicable)
Emberá-Chamí	'CMI '	cmi
Northern Emberá	'EMP '	emp
Pilagá	'PLG0'	plg

Other Emberá languages could also have Language System Tags:

Language System	Language System Tag	Corresponding ISO 639 ID (if applicable)
Emberá-Baudó	'BDC '	bdc
Emberá-Catío	'CTO '	cto
Epena	'SJA '	sja
Emberá-Tadó	'TDC '	tdc

References:

• "Alfabeto pilagá", Lengua pilagá, http://lenguapilaga.com.ar/web/alfabeto-pilaga/
• Dadyi Beꟈeada Ƀʌꟈia, Guía para docentes, República de Panamá, Ministerio de Educación - Dirección General de Educación, Unidad de Coordinación Técnica para la Ejecución de Programas Especiales en las Áreas Indígenas, Segundo Proyecto de Educación Básica / Banco Mundial, 2006, http://consulta.meduca.gob.pa/files/centroseducativos/etextos/GuiaLibroTexto_embera.pdf
• Asamblea Nacional, República de Panamá, "Ley 88 de 22 de noviembre de 2010 que recononce las lenguas y los alfabetos de los pueblos indígenas de Panamá y dicta normas para la Educación Intercultural Bilingüe", Gaceta Oficial Digital, no 26669-A,‎ 26 noviembre 2010, https://www.gacetaoficial.gob.pa/pdfTemp/26669_A/GacetaNo_26669a_20101126.pdf
• Comité de educación bilingüe ẽbẽra bed̶ea chamí, Ẽbẽra bed̶ead̶e b̶ʉd̶ai kuitáduru, karta A, Ediciones Manantial, Fundación Semillas, 2021, https://www.sil.org/resources/archives/93708

[PeterConstable]

If different languages use the same typographic convention, is it better to have distinct language system tags for each, or one that reflects the convention shared across multiple languages?

[moyogo]

Within the Chocó languages using letters with stroke overlay, the Northern Emberá and Emberá-Chamí conventions might be different.

The Northern Emberá Bible translation published in Panama uses diagonal strokes on the capitals but Dadyi Beꟈeada Ƀʌꟈia, Guía para docentes uses horizontal strokes. The official alphabet published Gaceta Oficial did not show the capitals.

The Comité de educación bilingüe ẽbẽra bed̶ea chamí’s syllabary uses the capital Ƀ as is instead of a B with a long stroke.

It would be good to have more reference documents in both but this is difficult.

Pilagá is not related to Chocó languages.

[PeterCon]

See the OT 1.9.1 alpha for draft revisions addressing this issue.