Mil'al vs. Milra on "Lamah"

Question

In a few places in the Torah, the word למה is pronounced מלעיל (accent on 1st syllable) and in other places מלרע (accent on 2nd syllable.)

I viewed Bemidbar 11:11 which has both in the same verse. The 1st one has a mahpach under the word is מלרע , and the 2nd has a tevir and is מלעיל . The 2nd is not a case of נסוג אחור.

Is there a difference in meaning with these two versions, and if so, what is it? Otherwise, what are the rules governing which one is used? Does it have to do with the trope note?

Answer 1

The word is spelled לָמָה (without a dagesh and stressed on the final syllable) when the following word begins with an א or ה or ע,* and spelled לָמָּה (with a dagesh and stressed on the penultimate syllable) in every other case.

There are eight exceptions to these rules (enumerated in Masora Gedola to Psalms 43:2): The three cases of לָמָה before letters other than אה"ע are Psalms 42:20, 43:2, and Job 7:20 (the latter case is also exceptional in being pronounced with penultimate stress despite not having a dagesh). The five cases of לָמָּה before אה"ע are II Samuel 14:31, Psalms 49:6, Jeremiah 15:18, I Samuel 28:15, II Samuel 2:22.

_{* Judging by the transcription here, it should be read אה"ע and not אח"ע. Masora Gedola to 49:6 says א"ה, but in this transcription it says אה"ע again, which is evidently more correct.}