Hi guys, how should I say 'I spoke in my mother tongue purposely so that you can't understand what I am talking about'. How should I say 'Sorry, I broke your vase accidentally, I will pay it' That is the above conxtext I give, can anyone help me? thanks...

ตั้งใจ dtung jai - on purpose, intentionally, to mean to do something

I spoke in my mother tongue purposely so you couldn't understand what I was talking about:

ฉันตั้งใจพูดภาษาแม่ เพราะไม่อยากให้คุณรู้ว่าฉันพูดเรื่องอะไร

chan dtung jai poot pah-sah mae, proeh mai yahk hai khoon roo wah chan poot reuang arai

ไม่ตั้งใจ mai dtung jai - by accident, unintentionally, to not mean to do something

Sorry, I broke your vase accidentally, I will pay for it:

ขอโทษนะครับ/ค่ะ ฉันไม่ได้ตั้งใจทำแจกันแตก ฉันจะจ่ายเงินให้เป็นค่าชดเชย

khaw toht na khrap/kha, chan mai dai dtung jai tum jae-gun dtaek, chan ja jaai ngern hai bpen khah choht choei

However, ไม่ตั้งใจ to me carries the connotation that you might be perceived as having meant to do what it is you said you didn't mean to do, like if you threw the vase on the ground in anger, not expecting it to break, and it broke, you might say ฉันไม่ได้ตั้งใจนะ!

If you don't expect that anyone would think you intended it to happen, you could use เป็นอุบัติเหตุ (bpen oo-but-het/oo-but-dti-het), "It was an accident!"

For example, ขอโทษครับ ฉันทำแจกันแตก เป็นอุบัติเหตุ (khaw toht khrap, chan tum jae-gun dtaek, bpen oo-but-het)

To those who read Thai, many apologies for my dreadful romanization!

Yesterday on television, Abhisit used the expression 'ไม่เจตนา' (mai jet-ta-na) , 'not deliberate'.

เจตนา is the formal Thai term for ตั้งใจ "intend" or ความตั้งใจ "intent". It's used as both a noun and verb.

So ไม่เจตนา might variously be translated as "unintentionally," "inadvertently," "accidentally" and so forth, depending on the context. ไม่เจตนา is also used in legalese to mean "involuntary," as in ฆ่าคนตายโดยไม่เจตนา "involuntary manslaughter," in order to distinguish from ฆ่าคนตายโดยประมาท "negligent manslaughter" and other related crimes.

มีเจตนา "to intend, to have intent"

ไม่มีเจตนา "did not intend (to)"

โดยเจตนา "intentionally"

โดยไม่เจตนา "unintentionally"

เจตนาร้าย "malicious intent"

เจตนาดี "good intent"

See also เจตนารมณ์, a formal compound created from เจตนา + อารมณ์ which has a similar meaning to เจตนา, but is only used as a noun: "intention, design, purpose." For example, เจตนารมณ์ของรัฐธรรมนูญ "constitutional intent."

thanks a million to Rick and Rikker

Don't forget Peppy! That response is the real answer to your questions. Mine was more of a tangent, because the main questions were already answered.