Thai transliteration without "special" characters

Starting consonants:
  k kh ng
  c ch
  t th d n
  p ph f b m
  y r l w s h '

Ending consonants:
  k t p
  ng n m
  y w '

Simple vowels:
  a  aa
  ae aeh *
  e  ee
  eo eoh *
  i  ii
  o  oo
  oe oeh *
  u  uu
  ue ueh *

Diphtongs:
  ia
  ua
  uea

* The 'h' in aeh/eoh/oeh/ueh is not written before ending w/y, since these are always long

Glottal stop (') can be omitted, e.g. aray, \kha, pramaan
Except:
(i)  when pronounced mid-word, e.g. khara'oke, du'^raay
(ii) when comes after a diphtong, e.g. \nia' [particle of surprise]
     to differentiate between the common (long) -ia/-ua/-uea, and the rare (short) -ia'/-ua'/-uea'

--

Differences from the scientific transliteration:
- ŋ => ng
- ɂ => '
- ɛ => ae
- ɔ => eo
- ə => oe
- ɯ => ue [also ɯa => uea]
- double-letter simple vowels are lengthened by h (ɛɛ => aeh, ɔɔ => eoh, əə => oeh, ɯɯ => ueh)
  except for syllables ending with w/y, where length is redundant
- different system for tones (see below), instead of aa/àa/âa/ǎa/áa

--

Differences form the ISO 11940-2 transliteration:
- i  => y   [as ending consonant]
- o  => w   [as ending consonant]
- o  => eo  [as an open-mid vowel]
- short/long vowels are not differentiated in ISO 11940-2
- tones are not shown in ISO 11940-2

--

Tones:
  1. mid:      may
  2. low:     _may
  3. falling: \may
  4. high:    ^may
  5. rising:  /may

Example:

\rueang kaa
kaa pen ^nok cha^nit _nueng. raw khon thay \riak man \waa kaa, ^phreo \waa man ^reohng "kaa kaa".
kaa mii /sii dam taa ^lae ...

--

Expert mode:

1. mid: ~may

- words starting with Mid-consonants (k/c/t/d/p/b/'):
  - open syllables: only write tone if not mid (1)
  - closed syllables: only write tone if not low (2)

- words starting with s/h:
  - open syllables: only write tone if not rising (5)
  - closed syllables: only write tone if not low (2)

- all other words:
  - open syllables: only write tone if not mid (1)
  - closed short syllables: only write tone if not high (4)
  - closed long syllables: only write tone if not falling (3)

Example:

\rueang kaa
kaa pen nok chanit _nueng. raw khon thay riak man \waa kaa, phreo \waa man ^reohng "kaa kaa".
kaa mii sii dam taa lae ...

===

Consonant system

|----------+--------+-----------+--------+-------+-----------+-------------+-------|
|          | Tenuis | Aspirated | Voiced | Nasal | Fricative | Approximant | Trill |
|----------+--------+-----------+--------+-------+-----------+-------------+-------|
| Glottal  | '      |           |        |       | h         |             |       |
| Velar    | k      | kh        |        | ng    |           | w           |       |
| Palatal  | c      | ch        |        |       |           | y           |       |
| Alveolar | t      | th        | d      | n     | s         | l           | r     |
| Labial   | p      | ph        | b      | m     | f         |             |       |
|----------+--------+-----------+--------+-------+-----------+-------------+-------|

Vowel system

|------+------------------+---------|
|      |     Unrounded    | Rounded |
|------+---------+--------+---------|
|      | Front   | Back   | Back    |
|------+---------+--------+---------|
| High | i  ii   | ue ueh | u  uu   |
| Mid  | e  ee   | oe oeh | o  oo   |
| Low  | ae aeh  | a  aa  | eo eoh  |
|------+---------+--------+---------|

List of allowed diphthongs/triphthongs

|---------------+---------------+---------------+------------------------------------|
| Starting with | Ending with y | Ending with w | Optionally ending with a consonant |
|---------------+---------------+---------------+------------------------------------|
| a             | -aay / -ay    | -aaw / -aw    |                                    |
| ae            |               | -aew          |                                    |
| e             |               | -eew / -ew    |                                    |
| eo            | -eoy          |               |                                    |
| i             |               | -iw           | -ia                                |
| o             | -ooy          |               |                                    |
| oe            | -oey          |               |                                    |
| u             | -uuy / -uy    |               | -ua                                |
| ue            |               |               | -uea                               |
|---------------+---------------+---------------+------------------------------------|

List of allowed consonant clusters

|----+-----+-----+-----|
|    | r   | l   | w   |
|----+-----+-----+-----|
| k  | kr  | kl  | kw  |
| kh | khr | khl | khw |
| p  | pr  | pl  | -   |
| ph | phr | phl | -   |
| t  | tr  | -   | -   |
|----+-----+-----+-----|