Thai G2P (grapheme to phoneme)

now still testing phase, not recommended for practical use

dictionary-based conversion -> web application

+BiLSTM seq2seq model (under construction)

in the dictionaries, each phoneme is encoded as one character as below

encoded one syllable consists of 4-5 characters according to general Thai syllable structure (C)CV(C)

• onset (1-2)
• vowel (1)
• coda (1)
• tone (1)

e.g.

• ปลา plA-1
• ธนาคารแห่งประเทศไทย Ta-4 nA-1 KAn1 hyN2 pra-1 TEt3 Taj1

dependencies

• pythainlp (for tokenization)
• tltk (for rule-based conversion)

import thaig2p

>>> thaig2p.g2p('ผมจะไปโรงเรียนพรุ่งนี้')
'phǒm càʔ pay rooŋ rian phrûŋ níi'

>>> thaig2p.g2p('หิวข้าวแล้ว', 'ipa', return_tokens=True)
[['หิวข้าว', 'hǐw kʰâːw'], ['แล้ว', 'lɛ́ːw']]

2 transcription styles: haas(default) or ipa

vowels

short 9 + long 9 + diphthong 3

phoneme	encoded	IPA	Haas
/อะ/	a	a	a
/อา/	A	aː	aa
/อิ/	i	i	i
/อี/	I	iː	ii
/อุ/	u	u	u
/อู/	U	uː	uu
/อึ/	v	ɯ	ɯ
/อือ/	V	ɯː	ɯɯ
/เอะ/	e	e	e
/เอ/	E	eː	ee
/แอะ/	y	ɛ	ɛ
/แอ/	Y	ɛː	ɛɛ
/โอะ/	o	o	o
/โอ/	O	oː	oo
/เอาะ/	x	ɔ	ɔ
/ออ/	X	ɔː	ɔɔ
/เออะ/	z	ə	ə
/เออ/	Z	əː	əə
/เอีย/	J	iə	ia
/เอือ/	W	ɯə	ɯa
/อัว/	R	uə	ua

consonants

21 + no coda

phoneme	encoded	IPA	Haas	used as coda
/บ/	b	b	b
/ป/	p	p	p	✅
/พ/	P	pʰ	ph
/ม/	m	m	m	✅
/ฟ/	f	f	f	few
/ด/	d	d	d	few
/ต/	t	t	t	✅
/ท/	T	tʰ	th
/น/	n	n	n	✅
/ส/	s	s	s	few
/ร/	r	r	r
/ล/	l	l	l	few
/จ/	c	tɕ	c	few
/ช/	C	tɕʰ	ch
/ก/	k	k	k	✅
/ค/	K	kʰ	kh
/ง/	N	ŋ	ŋ	✅
/ว/	w	w	w	✅
/ย/	j	j	y	✅
/ห/	h	h	h
/อ/	?	ʔ	ʔ	disputable
no coda	-

in this program, define possible clusters/onsets/codas as below

CLUSTERS = ["br","bl","pr","pl","Pr","Pl","fr","fl","dr","tr","Tr","kr","kl","kw","Kr","Kl","Kw"]
ONSETS = ["b","p","P","m","f","d","t","T","n","s","r","l","c","C","k","K","N","w","j","h","?"]
CODAS = ["p","m","f","t","d","n","s","l","c","k","N","w","j","?","-"]

undecodable characters will be ignored

>>> thaig2p.decode('mAt3 trA-1 ABC あいう',)
'mâat traa ABC あいう'

Note for myself

• ควรจะลบ final glottal stop ? ทุกตัวหรือไม่ (ไม่ใช่ phonological)
• จัดการ tone ของ light syllable อย่างไร เช่น สบาย /sa?2 baaj1/ or /sa1 baaj1/
• "ไทมส์" ทำไงดี (/thajm/ มี coda สองตัว ซึ่งไม่ตามหลักการ)
• เวลาเทรน ใช้ End-to-End model ซึ่งแปลงอักษรไทยไป phone โดยตรง (ไม่ต้องตัดคำก่อน)
• ผลลัพธ์ของ decoder เป็น tuple (onset, vowel, coda, tone)
• อาจจะใช้ attention หรือ CNN ใน encoder