Prepositions

Prepositions in Thai indicate relationships of place, time, direction, and manner, much like in English, but they often behave more like particles attached to verbs or nouns rather than standing entirely on their own. A common pattern is to place the preposition directly after the noun or verb it relates to, with no change in form for case or number. Because Thai lacks inflection, the same preposition word works for singular and plural, and context tells you exactly what's meant.

When expressing location, the preposition อยู่ (yùu) often follows a noun to mean “at” “in” or “on.” It literally means “to exist,” but in this role it marks the place where something is. For example:

โรงเรียน

อยู่

ตรงนั้น

(“The school is over there.”)

To indicate direction or movement toward a place, you use ไป (bpai, “go to”) or มา (maa, “come to”) after the verb, sometimes followed by the place noun:

ไป

ตลาด

(“(I) go to the market.”)

มา

บ้าน

(“(You) come to the house.”)

For time expressions, you simply place the time word before or after อยู่ or the verb, often without a separate preposition. However, to mean “before” or “after,” Thai uses ก่อน (gòn) and หลัง (lǎng). These follow the time noun:

หนึ่งชั่วโมง

ก่อน

(“one hour before.”)

สองวัน

หลัง

(“two days after.”)

When describing the instrument or means by which something is done, the preposition ด้วย (dûay, “with” or “by”) follows the agent or tool:

เขาเขียน

ด้วย

ปากกา

(“He writes with a pen.”)

To express accompaniment—“with someone”—you place กับ (gàp) before the person's noun:

ไป

กับ

เพื่อน

(“(I) go with a friend.”)

Some prepositions combine with verbs to form compound words that you memorize as single units. For example, รอ (rɔɔ, “wait”) plus ให้ (hâi, “let”) becomes รอให้ (rɔɔ hâi, “wait for”), and เข้า (khâo, “enter”) plus ไป becomes เข้าไป (khâo bpai, “go in”). These compounds behave like verbs rather than noun modifiers.

Because Thai does not change prepositions for gender, number, or case, the key to mastering them is memorizing which preposition pairs with which verb or context. Practice by pairing กิน (gin, “eat”) with ที่ (thîi, “at”) for “eat at [place]”—กินที่ร้าน—and by using ก่อน and หลัง with various time words. Over time, the simplicity of uninflected prepositions will help you express complex spatial, temporal, and instrumental relationships with just a few reliable particles.

Verbs

Thai verbs never change their form to indicate person, number, or tense. You learn one verb root and use it in any context. Instead of conjugating the verb itself, Thai relies on particles placed before or after the verb to show time and aspect. This keeps verb usage remarkably consistent and predictable.

To talk about future actions, you place จะ (jà) before the verb. It means “will” or “going to.” For example:
จะ ไป
(“will go” / “are going to go”)

When you want to show that something is happening right now, you use กำลัง (gam-lang) before the verb. It marks the present continuous:
กำลัง อ่าน
(“is reading” / “am reading”)

To indicate a completed or past action, you put แล้ว (láaeo) after the verb. It can mean "already" or simply mark past tense:
กิน แล้ว
(“ate already” / “has eaten”)

Negation in Thai is equally simple. คุณวาง ไม่
is formed by placing ไม่ (mâi) before the verb. It turns any verb into its negative form:
ไม่ ชอบ
(“do not like”)

A very common pattern combines aspect markers with อยู่ (yùu) after the verb to emphasize an ongoing state or action. This is often used in spoken Thai to stress continuity:
กำลัง อ่าน อยู่
(“is in the middle of reading”)

Because the verb itself remains unchanged, once you know a handful of particles and a basic verb root, you can express any temporal nuance—future plans, ongoing activities, completed events, and negation—with just a few extra words. Practice combining different particles with your most-used verbs, and soon you'll deploy any tense or mood as naturally as native speakers do.