Why? Which "Why"?
In the Hebrew language there are two words which mean “why?” — madua and lamah. In many instances these two words seem to be used interchangeably. In fact, some early grammarians such as Ibn Parchon and the Radak explain that the two words are synonymous. Nonetheless, as we have demonstrated time and again, the Hebrew language is not mere happenstance, and no two words can mean exactly the same thing. So how can we differentiate between madua and lamah?
Rabbeinu Yonah ibn Janach (990-1050) writes in his Sefer Rikmah (also cited by Radak) that madua is a contraction of the phrase mah deah, which means “what thinking”, as if to ask what thinking or rationale there is behind a certain occurrence or action. This explanation is also found in the commentary of Ibn Ezra (to Exodus 18:14), and is alluded to by Nachmanides (to Genesis 30:20) who writes that madua is a contraction of two words, but does not elaborate further.
The word lamah can similarly be seen as a compound word made up of the prefix la- which means “for” and the root word mah “what”. Accordingly, when one asks lamah one asks for what objective does such-and-such exist.
Partially based on these ideas, Rabbi Yaakov Tzvi Meckelenberg (Ha’Ktav V’Hakabbalah to Exodus 5:4) and the Malbim explain that when one asks madua, he means to question what is the effective cause of something, while lamah asks for its ultimate purpose (i.e. its final reason).
In a slight departure from this approach, Rabbi Shlomo Aharon Wertheimer explains that madua is used when one questions the cause of something seemingly bizarre or out of the ordinary. On the other hand, lamah has the connotation of asking “why” in a complaining fashion (e.g. “Why are you doing this to me?”) or with a rebuking tone (e.g. “Why did you do such-and-such?”). The word lamah has the implication that the matter at hand is somehow wrong, while madua simply asks for more information without implying anything positive or negative. Similarly, others explain that the word lamah is used when rhetorically asking “why”. Meaning, one who asks lamah does not expect a serious answer; he simply wants to state his objection. When one uses the word madua to ask “why” he genuinely seeks to address his query, and anticipates a true answer.
Some explain that the word madua is specifically used when questioning the rationale of a specific ruling or command, while lamah can be used to ask why in other contexts.
To summarize, there are two words in Hebrew which mean “why”: lamah and madua. While some authorities try to explain that the two words are equivalent, others find slight differences in their connotations. Some explain that lamah seeks to find the ultimate purpose of something while madua seeks to find its immediate cause. Others explain that lamah implies something negative about that which he is questioning, while madua has a neutral implication. A third view explains that why-questions using lamah are generally meant rhetorically, while such questions using madua seek an answer in earnest.
All of these different nuances are reflected in a simple word change in Hebrew, but in English, we’re stuck with just asking: “Why?”