I found that the languages are hard to break into as an amateur, owning to the available literature. In contrast Egyptology has many popular treatments, you just have to watch out for the junk.
The vendor proudly showed us a new acquisition, an ancient cylinder seal. The archeologist examined it and told him it was a fake, because he explained, "I can read this language, and it is gibberish."
The UCLA archeologist, then excavating at Tel Mozan with Giorgio Buccellati, had 2 dead languages under his belt, a requirement for his Phd. I was rather in awe of the fellow - 2 dead languages!
Pro-tip: never buy artifacts without an archeologist to advise you. It's likely ethically wrong anyway, and likewise stupid unless you're an expert.
All this to say I have infinite respect for someone who'd learn a dead language, let alone two. I'm glad someone is doing this work, and fortunately it's not me.