asking a question in Thai

[janvanwim]

This is my first visit to this forum.
I just started learning Thai.
My book gives me 3 different ways of asking the same question e.g
What is this? nu araj / nu khue araj / nu pen araj
Can anyone explain why this is and if there is a difference between each possibilty and what the diffence should be about or what?
I cannot figure this out myself.
Thank you so much and kind regards. janvanwim

[pichai]

A: What is this? /ni arai/
B: A pen. /bpaak gaa/

A: What is this? /ni khue arai/
B: A pen. /bpaak gaa/

A: What is this? /ni bpen arai/ (rarely used)
B: A pen. /bpaak gaa/


Hope it's not so confusing?

[janvanwim]

Thanks Pichai: may I simply conclude there are two (normally used) ways of asking the same question and it is up to the speaker to decide which one he (or she) will use? Possibility no 3 (the one with: pen) is rarely used. Is that correct?
Thanks again and kind regards, Jan

[someone else]

In normal everyday speech, there are two words for "is", khue and bpen. Often, they are interchangeable but sometimes not. Usually, to say what is this, you would say

"ni khue arai" or just "khue arai"

You wouldn't say "ni bpen arai" for what is this. "bpen arai" on its own means "What is the matter ?"

[janvanwim]

Dear Someone Else,
Thanks for your explanation.
Answers like these make it much easier to understand what Thai langauge is about and how to handle it. Thanks again and kind regards, Jan.