YOU SAID:
please can I have a coffee?
INTO JAPANESE
コーヒーをいただけますか。
BACK INTO ENGLISH
Can I have some coffee.
INTO JAPANESE
コーヒーを飲めますか。
BACK INTO ENGLISH
Can you drink coffee?
INTO JAPANESE
あなたはコーヒーを飲むことができますか?
BACK INTO ENGLISH
Can you drink coffee?
That didn't even make that much sense in English.