Support Raglai (in Viet Nam) writing system

[Raglai](https://en.wikipedia.org/wiki/Raglai_people) (Raglei) is a ethnic group in Viet Nam. Their writing system is based on Latin, modeled after the system used for Latin-based Vietnamese (Quốc ngữ).

Some sample texts:

| Raglai | Vietnamese | English |
|--------|--------|-------|
| Sơ'rắmp vák rơc'clày | Tiếng viết raglai | Raglai writing |
| Mơ'nhìh tơ'lờu | Âm trước / Phụ âm đầu | Initial consonant |
| Mơ'nhìh cơ'lóch | Âm theo / Nguyên âm | Vowel |
| Mơ'nhìh mơ'hík | Âm vang | Final consonant |
| Mơ'nhìh pāh | Âm dẫn | Tone marks |

## Consonants

C B D Đ G H
L M N V S R X
P Q K T Ph TR CH GH GI
NG NH NGH KH TH

## Vowels
A Ă Â E Ê I O Ô Ơ U Ư Y