How did "Aaron" get his two "a"s when transliterated from Hebrew?

See subject.

I like the two a’s. Front and forward: I’m here. And just because I can, here’s me again.
You have to listen to letters sometimes.

Its English form is derived from the Hebrew “Aharon” (אהרן) which is most likely of Ancient Egyptian origin (from “aha rw” meaning “warrior lion”; or from Aaru, a heavenly paradise). According to other theories, the name could be derived from various Hebrew roots meaning “high mountain”, “mountain of strength” or “enlightened”, or “bearer of martyrs”. The rest is just the average problems with transliteration.

So the double A is to tell you that both 'A’s should be vocalized.

Also, at least in modern Hebrew (I don’t know about ancient Hebrew), the letter Hay (ה) is a very weak – nearly silent – consonant. So I can see how it drops out in transliterations.

Because that was the way Moses pronounced it?

So why did Immanuel get 2 m’s when both of the original languages have single letters?

The spelling “Aaron” is a letter-for-letter translation of Koine Greek into Vulgar Latin

That’s a bit arbitrary. Notice that the Wiki page for Immanuel shows it spelled with either one or two m’s.

Notice that the letter Mem (מָּ) in the name has a dot inside of it. It is a quirk of the Hebrew spelling and syllable rules that a consonant can behave as if it were a double letter – it can serve as the final letter of a syllable and simultaneously as the first letter of the following syllable (sort of). The dot inside the letter indicates that this is happening. Very roughly speaking, it is sort of equivalent to the English practice of doubling consonants in some places. I’m going to guess here, that such cases would be transliterated into English letters with a double consonant.

Hebrew is typically written without showing the vowel marks, and also not showing the dagesh marks (dots inside). So you don’t always see it, but you have to know it’s there.

And as a WAG possibly to make clear it is a short i.

Senegoid made the exact same point I was going to say, and probably explained it even better than I would have.

The ‘double m’ comes straight from the ‘double mu’ in the Greek Septuagint.

Maybe you knew this, but this is doubly witty, because Moses stuttered.

Time to look up other names “Aha-” names in the Bible. “Ahashveros” (Purim) WAG is non-Hebrew.

Also, like everything else on the Bible, I’m sure many have looked at this. All I gotta do is find 70 people to agree.

I think most or all of the names from Esther are non-Hebrew, and presumably they are Persian. This includes many non-Hebrew names that have become common Jewish given names, and thus “adopted” into Hebrew, just as many Hebrew names have been “adopted” into English. In particular, Mordecai and Esther are not of Hebrew origin, although they are popular Jewish/Hebrew names to this day.

Here’s another non-Hebrew name: Moses. The Bible goes to pains to find some Hebrew meaning for it, saying " . . . because I drew him from the water . . . " (was it Pharaoh’s daughter who said that? If so, she probably wasn’t speaking Hebrew!) Actually, the morpheme “mose” (and variants) simply means “son” or “son of”. Examples: Thutmose (son of Thoth), Rameses (son of Ra). So Moses is actually a name of Egyptian origin.

ETA: Also, IIRC, Haman isn’t a name at all, Persian or otherwise. It’s actually the guy’s title. In one edition of The Book of Esther that I saw, it was spelled Aman, and used in phrases like “the king’s Aman”.

Did he also name the aardvark?

So that he would be listed at the first page of the Hebrew telephone book.

Elendil’s Heir:

No, it was Adam who named the animals. Genesis 2:19.

It’s from the ancient Hebrew “aharad varakh” (אהרד ברך), meaning “[King of Babylon] who [crawled] in the grass eating ants/termites”, popular epithet for Nebuchadnezzer.

(Just kidding. I confess I just made that up, lest I be damned to שְׁאוֹל (the Pit) by Dopers, who, y’know, actually know Hebrew.)

because when he was in line at Ellis Island someone else already had that name so the imigration officer just put in an extra “a” simple stuff really …

now you don’t have to ask cecil

Even as a joke, I thought we all knew that no names were ever changed at Ellis Island.

I’m not so sure about that. In all the versions of the Purim story I’ve ever heard, Haman is definitely supposed to be the guy’s name and not a title. There are even preserves-filled cookies that we’ve given the name “Haman’s Ears” to specifically to poke fun at that particular dude. And plus Wikipedia says

I don’t know, maybe he made everyone call him the Persian words for “Mr. Magnificent” or something.