Why is the inherent vowel after the 'บ' in 'บริษัท' pronounced as 'aw' where I would expect it to be 'a' ?

zhilong,

I found in Mary Haas "The Thai System of Writing" > chapter 4, initial consonants > section 6, page 51, the intrudel vowel /-aw-/

"in special cases an initial consonant grouping which cannot be pronounced as a true consonant cluster is pronounced in two syllables by the intrusion of /-long aw-/ or sometimes /-short aw-/ in rapid speech if the first consonant is middle or low. most of the groupings which come in this category contain บ, ม, ท, or ธ followed by ร, but other types of examples occur sporadically"

บริษัท is one of the examples given.

I am trying to hash out all of these devil in the details type scenarios also. would be more than happy to post more examples if you do not happen to have this book.

Why is the inherent vowel after the 'บ' in 'บริษัท' pronounced as 'aw' where I would expect it to be 'a' ?

From "หลักภาษาไทย" by กำชัย ทองหล่อ, page 501:

พยัญชนะบาลีและสันสกฤตที่ไม่มีรูปสระ ตามปรกติ ต้องอ่านมีเสียงสระ "อะ" กำกับ แต่ในกรณีต่อไปนี้ต้องอ่านมีเสียงสระ "ออ" กำกับ คือ:

ก. เมี่อใช้ตัว "ร" สะกด เช่น: สมร, อัมพร, อมร, อนุสรณ์,ม สังสร ฯลฯ

ข. เมื่อแผลง "ป" เป็น "บ" เช่น: บดี, บรม, บริการ, บริขาร, บริบูรณ์, บริโภค, บริวาร ฯลฯ

Pali and Sanskrit consonants which are not accompanied by an explicitly written vowel normally must be pronounced with an /a/ sound. In certain cases, however, these consonants must be pronounced with an /o/ sound. These include:

a. When the letter /ร/ is the last letter in a syllable or word [see the examples] [the vowel sound before the ร is pronounced as /ออ/.

b. When the [sanskrit or Pali] word [converts] the letter /ป/ into /บ/, [then the implied vowel sound is the /ออ/ sound.

Kumchai mentions several other instances as well.