Japanese is awkward. どうして来ないのですか。 Why don't you come? どうして来るのですか。招待していなのに。 Why do you come?
Miki
Do you know「来る」カ行変格活用?
Miki
→Kuru's 'ka' line conjugation? ;-) -ve くる→こない
Amatuka
I don't know if it help you lean 来る conjugation. It is also said to be カ行の三段 in a dictionary but I leant as カ行変格活用 at school as a child. 「こ・き・くる・くる・くれ・こい」 来ない・来ます・来る。・来るとき・来れば・来い!
Miki
どうして来るのですか。招待していなのに。 Why do you come?
The above is rather ambiguous. The English translation should be "Why do you want to come,even when not invited."
Besides, the expression is pretty rude. Consider: どうしてお出でになりたいのですか、ご招待申しあげてもいませんのに.
bamboo4
bamboo
I have never said "why do you want to come, even when not invited" in my entire life. (native English speaker)
A natural translation would be "Why are you coming? I didn`t invite you."
English is a little more direct than Japanese. translating a phrase word for word never sounds natural.