เคย

In the patterns shown here, เคย precedes a predicate and can express a previous experience or a past habit or state. English 'have done before', 'have ever', or 'used to' are possible renderings, chosen from context rather than separate Thai tense conjugations. The written pronunciation shown here has a mid tone.

1. Placement
A pattern in this lesson is: [Subject] + เคย + [Verb] + [Object].
Example: ผมเคยกินส้มตำ (I have eaten papaya salad before).
เคย can also precede an adjective functioning as a predicate to describe a past state. English 'used to' can suggest a contrast with the present, but whether the state has ended depends on the full context.
Example: เขาเคยอ้วน (He used to be fat).

2. Negation (Never vs. Not Yet)
To say you have 'never' done something, place ไม่ before เคย.
Structure: [Subject] + ไม่เคย + [Verb].
Example: ฉันไม่เคยไป (I have never gone).
To emphasize that you have 'never done it before', you can add มาก่อน (maa kɔ̀ɔn) at the end: ฉันไม่เคยไปมาก่อน (I have never been before).

To say you have not experienced something yet, one pattern uses ยังไม่ before เคย.
Example: ผมยังไม่เคยไปเชียงใหม่ (I haven't been to Chiang Mai yet).

3. Asking Questions
The following three patterns ask about experience; they are not an exhaustive list of Thai question constructions:
• [Subject] + เคย + [Verb] + ไหม?
Example: คุณเคยไปเมืองไทยไหม? (Have you ever been to Thailand?)
• [Subject] + เคย + [Verb] + หรือเปล่า?
Example: คุณเคยไปเมืองไทยหรือเปล่า? (Have you ever been to Thailand?)
• [Subject] + เคย + [Verb] + หรือยัง? (Have you... yet?)
Example: คุณเคยกินทุเรียนหรือยัง? (Have you tried durian yet?)
Note: A question with เคย and หรือยัง can concern whether an experience has happened yet. An expectation or opportunity may come from the situation, as in 'Now that you are in Thailand, have you gotten around to trying durian yet?'; it is not a guaranteed future event. With pronoun dropping, the person being asked must be recoverable from context. Compare คุณเคยไปไหม? and เคยไปไหม?; this example does not establish a frequency rule or a universal preference.

Short Answers:
Short replies depend on the question and the intended experience. The following forms can be used in an appropriate context:
• Affirmative experience: เคย (khəəy)
• Experience already acquired, where this answers the หรือยัง question: เคยแล้ว (khəəy lɛ́ɛw)
• No previous experience: ไม่เคย (mây khəəy) or ยังไม่เคย (yang mây khəəy)
• Not yet, where the omitted experience is understood from a หรือยัง question: ยัง (yang)

4. Past Habits and Emphasis
เคย can introduce a past habit or state. A contrast with the present may be understood from the situation, but cessation is not guaranteed by the marker alone. A time expression such as เมื่อก่อน (mʉ̂a kɔ̀ɔn - in the past) can locate the statement in an earlier period. For example, เมื่อก่อนผมเคยสูบบุหรี่ (In the past, I used to smoke). To add emphasis to an experience, you can add มาก่อน (maa kɔ̀ɔn - before) at the end of the sentence: ผมเคยกินมาก่อน (I have eaten [it] before).

5. Nuance: 'Used to' vs. 'Accustomed to'
Distinguish the experience or past-habit construction from เคยชิน (khəəy chin), which means 'to be accustomed to' or 'used to' a situation. The related word ชิน (chin) can mean 'used to' or 'accustomed to' (e.g., ชินแล้ว = I'm used to it). The dictionary also records a familiarity or accustomed sense for เคย itself; it is not restricted to compounds. Compare the complete expressions, including เคยตัว (khəəy tua - spoiled/accustomed to bad habits) or เคยมือ (khəəy mʉʉ - accustomed to doing something by hand).

6. Nuance vs. Completion
Compare เคย with แล้ว. While แล้ว can indicate that an action is completed or a situation has changed (e.g., 'I already ate lunch'), เคย can mark a previous experience (e.g., 'I have eaten durian before'). Neither 'just finished' nor a specific completed trip follows automatically from the marker. They are not mutually exclusive, as the earlier short-answer example also shows.