The hidden a, and syllables that borrow a class

Some syllables contain a short a that isn't written at all. When a consonant has no vowel and another syllable follows, slip in a quick a: สบายsà-baai is s(a) + baai.

• สบายsà-baai well, comfortable
• ทหารtá-hǎan soldier
• ธนาคารtá-naa-kaan bank
• สถานีsà-tǎa-nii station

The hidden a is short, so its syllable is dead: low for mid- and high-class letters (สบายsà-baai), high for low class (ทหารtá-hǎan).

Borrowing a class

Now the clever part. If the second syllable starts with a humming letter (งngaw, นnaw, มmaw, ยyaw, รraw, ลlaw, วwaw), it takes the class of the first consonant, exactly like a silent หhǎw:

• ขนมkà-nǒm (snack): on its own นมnom (milk) is mid, but here it follows high-class ขkǎw and rises
• ถนนtà-nǒn (road): rising, following ถtǎw
• ตลาดdtà-làat (market): on its own ลาดlâat would fall, but after mid-class ตdtaw it's a dead syllable with a low tone
• สนุกsà-nùk (fun), สวัสดีsà-wàt-dii (hello): high class, dead, so low
• อร่อยà-ràwy (delicious): the second syllable follows mid-class อaw, and with ◌่mái-èek that's low

Hidden aw

A consonant followed by รraw with no vowel often reads aw: บริษัทbaw-rí-sàt (company), ละครlá-kawn (TV drama).

Linking a

In some compound words an extra a links the parts: ผลไม้pǒn-lá-máai (fruit) is pǒn + lá + máai.

How to handle these words

The spelling doesn't always tell you whether a hidden a is there, so learn these as whole words and let the rules explain their tones. The more you read, the more natural it feels.

Typical mistake: reading ขนมkà-nǒm with a mid tone on the second syllable. The borrowed class makes it rise.