ตั้งแต่ since

ตั้งแต่ since 

ทำไมถึง ไม่ช่วย ตั้งแต่แรก ล่ะคะ

Why​ you did not help me from the beginning?

The Thai word ตั้งแต่ (dtâng dtâi) means "since" or "from."  It indicates a starting point in time or a range of time.  It can refer to a specific point in the past, or it can indicate a duration of time.

Here are some examples illustrating its usage and possible English translations:

**Example 1:  Indicating a specific point in the past.**

* **Thai:**  ตั้งแต่ฉันเรียนจบ (dtâng dtâi chǎn rian jòp)

* **English:** Since I graduated. / From the time I graduated.

**Example 2:  Indicating a duration of time.**

* **Thai:**  ตั้งแต่เช้าจนถึงเย็น (dtâng dtâi cháo jon thʉ̌ng yen)

* **English:** From morning until evening. / From morning to evening.

**Example 3:  Indicating a range of time.**

* **Thai:**  ตั้งแต่ปี 2560 จนถึงปัจจุบัน (dtâng dtâi pii 2560 jon thʉ̌ng pàt-chu-ban)

* **English:** From 2017 until now. / Since 2017.  (Note: 2560 is the Thai Buddhist year equivalent to 2017.)

**Example 4:  Indicating a cause-and-effect relationship.**

* **Thai:**  ตั้งแต่มีโทรศัพท์มือถือ ชีวิตก็เปลี่ยนไป (dtâng dtâi mii tho-ra-sàp mʉʉ thʉ̂ː chîwit gɔ̂ pliɛn pai)

* **English:** Since the advent of mobile phones, life has changed. / Life has changed since we got mobile phones.

**Example 5:  A more nuanced example:**

* **Thai:**  ตั้งแต่ฉันรู้จักเธอ ฉันก็มีความสุขมากขึ้น (dtâng dtâi chǎn rúu-jǎk thǝə chǎn gɔ̂ mii khwaam sùk mâak khʉ̂n)

* **English:** Since I met you, I've been much happier. / My life has been much happier since I met you.

The word ตั้งแต่ (dtâng dtâi) is versatile and can be used in various contexts to indicate a starting point or a period of time.  The specific English translation will depend on the context of the sentence.