Collounsbury is right that ‘no’ in Arabic is lâ. ‘Yes’ is na`am, and ‘why’ is li-mâ dhâ.
In Hebrew, ‘no’ is lo (you can see the relationship to Arabic, compare salâm / shalom: Arabic a corresponding to Hebrew o). ‘Yes’ is ken (which is probably related to the Arabic word kâna ‘to be’; the Arabic word for ‘yes’, na
am*, is related to the Hebrew word for pleasure and delight, also *naam).
The Modern Greek word for ‘yes’ is nai, which sounds just like the English negation nay! Weird, isn’t it?
MEBuckner and Short correctly noted that the Japanese word for ‘no’ is iie. Want to know something funny? Check this out:
In Turkish, the native word for ‘no’ is yok. But this is a very abrupt sound, as rude as a punch in the nose. Turks are very polite people, so they needed a more genteel way to say ‘no’. The polite Persian way to say ‘no’ is na khayr, a compound of na ‘no’ and the Arabic word khayr, ‘good’. It’s as if to say, “I’m afraid the answer is no, but I wish the good for you anyway.” The Turks made it even more polite by deleting the negative and they just say the word for ‘good’, pronounced hayïr in Turkish. So the really polite Turkish way to say ‘no’ is hayïr, literally ‘good’.
The Japanese word iie ‘no’ looks similar to the Japanese word for ‘good’, ii. But the Japanese word for good is pronounced exactly the same as the native Turkish word for ‘good’ – iyi. So ‘good’ and ‘no’ have this fascinatingly interwoven strands between Turkish and Japanese. (Japanese has been linked to the Altaic family of languages, to which Turkish belongs.)
Hungarian does so have words for ‘yes’ and ‘no’! They are igen and nem.
Negatives in n- are common to nearly all Indo-European languages; some examples that haven’t been mentioned are Hindi nahîm, Persian nâ, and Russian nyet.
Verbal negatives in m- are found in Classical Greek (mê), Persian (ma-), Hindi (mat), and Turkish (-mi).