Khmer script

Khmer script is the writing system used to write the Khmer (Cambodian) language. The script is an abugida. An abugida is a special type of writing system where consonants are changed to make a sound. The Khmer writing system came from other writing systems in India. It was the writing system that Thai and Lao are based on. However, Thai and Lao added tone markers to better suit their own languages, since Thai and Lao are tonal, while Khmer is not. 
Letters.
Consonants.
Khmer has 35 consonants, but 2 of them are not used anymore. There are two categories of consonants: A-series and O-series. The A-series consonants end with an -"aw" sound (/ɑː/ in IPA) but the O-series consonants end with an -"oh" sound (/ɔː/ in IPA). For instance, ក (/kɑː/, "neck") is pronounced "kaw" and គ (/kɔː/, "mute") is pronounced "koh". Both of them have the "k" sound but they end in different sounds because ក is A-series while គ is O-series.
One key feature that Khmer has, while Thai and Lao do not, is that consonant letters have subscript forms. Subscript forms are forms of consonant letters that are written underneath other letters. Similar to how different letters in the Latin alphabet have capital or lowercase forms that look different from each other, consonants in Khmer have standard and subscript forms. These are used to write consonant strings. For example, in the word Khmer (ខ្មែរ), the "kh + m" consonant string is written as ខ្ម. By themselves, the consonants that make up the "kh + m" cluster would be written as ខ and ម, but since the "m" consonant is the second part of a consonant string, it is written differently under the first consonant in the cluster ខ. So ្ម is the subscript form of ម.
Vowels.
Dependent Vowels.
Dependent vowels must be combined with a consonant to make a sound. Different sounds are made depending on whether or not a consonant is voiced or voiceless.
For example, the A-series consonant ត is pronounced "taw" by itself. However, when combined with the vowel ា (which makes an -"ah" sound when added to an A-series consonant), it becomes តា ("tah", which means "grandfather").
However, the O-series consonant ទ (pronounced like the English "toe") combined with the vowel ា makes the word ទា (tee-ah) and means "duck".
Independent Vowels.
There are independent vowels that do not need to be combined with a consonant. These are usually used to used to write words from Sanskrit and Pali. An example is ឧសភា (oo-sa-PEE-ah, "May"), where ឧ makes a sound like "oo" in b"oo"t.
Numbers.
Khmer has its own way of writing numbers. The numbers in Khmer are ០១២៣៤៥៦៧៨៩. For instance, 2022 in Khmer would be ២០២២.