from what the first comment said,, in my opinion i feel weird when someone talk to me like that 'cause its so polite anyways it's good to say to older people but some of them the word she write is fine so, im gonna write some of the word in normal way when you say to your friend or someone you close ! ^^ what are you doing?- ทำไรอยู่หรอ tum lai yoo lor? ทำไรอยู่ tum lai yoo? ทำอะไรอยู่ tum alai yoo? Maybe- มั้ง? mung? miss you- คิดถึงนะ! kid teung na ! in my opinion, normally ppl dont say i when they said this for ''I'' you better use the word ,,เรา rao,, instead ฉันchun 'cause it's really weird ! :D ADD ** love you- รักนะ rak na dear/baby- ที่รัก tee rak good night/have a nice dream- ฝันดีนะ fun dee na / ฝันดี fun dee gotta go- ต้องไปแล้วนะ tong pai laew na / ต้องไปแล้ว tong pai laew for adding ''ka'' at the end it doesn't mean to be polite only but somehow it make you look cute when you add ka at the end X'D

Moreover from the answer above, u may notice she put a word "ค่ะ kha". It is a polite word for woman which always put at the end of each sentence. (from your question, i guess u know that as well) For the other word, I love you = ฉันรักคุณ (Chan ruk khun) ็Have you eaten? = กินข้าวแล้วหรือยัง (frankly, i cant spell how to pronounce in english!!! so difficult) I am so hungry. = ฉันหิวแล้ว (Chan hew laew) How could i go there? = ฉันจะไปที่นั่นได้อย่างไร? (Chan ja pai tee nun dai yang rai?) Hou much does it cost? = ราคาเท่าไหร่? (Rar kar thao rai?) anything u wanna know, feel free to ask more question. I think Ting over there and I, we both glad that the other people in the world interested in THAI.

What's up\What are you doing? เป็นไง pen-ngai/ ทำอะไรอยู่หรือคะ tum-arai-you-reu-ka Yes (อืม um /ค่ะ ka /ใช่ค่ะ chai-ka) Maybe น่าจะ naa-ja Who\What\When\Where\Why ใคร krai /อะไร arai/ เมื่อไหร่ mue-rai/ที่ไหน tee-nai/ อย่างไรyaang-rai This\That\Then\Than นี้ nee /นั้น nun /(ดังนั้น dung-nun/หลังจากนั้น lung-chak-nun/แล้ว laaw)/กว่า gwah I miss you ฉันคิดถึงคุณ chun-kid-thung-khun I want to go home. ฉันอยากกลับบ้าน chun-yahk-klub-baan

I agree with Lollipopism :D I translated to quite polite.I'll try to add more trendy words. lol~ But I still write the polite one for the basic starting too. :)

Yes. I found that how to write Thai word with the pronunciation in English is quite difficult. Sorry for any mistakes :D From Pipe : กินข้าวแล้วหรือยัง may be 'gin kao laaw/laew reu young'?