My theory on Dipper's real name.

My thought was that due to Mabel being relatively similar to Ariel, however with one less syllable and an M at the start, and going by Alex's hint that the twin's names have a similarity, I tried Alex minus 1 syllable with an M at the beginning and I got Max.

Then while watching a YouTube video I stumbled upon a comment by a YouTuber going by the name of "DragonhunterZeroSeven Nineteen" who seemed to have the same idea and more. He said that his name would specifically be MAXINE, as in Maxine - a girl's name, giving him a plausible reason not to use it, hence constant use of a nickname. This seems a lot more sensible than other theories I have seen online and one I stand by.

Oh well, I guess we have to wait until journal 3 comes out...