Linguistics
How to Learn a Language
Immersion is the name of the game. If you're familiar with AJATT or Refold, then there you go. If not, have a look.
I also recommend Learning with Texts or LingQ. (and Steve Kaufmann) These are applications that allow you import any text, and as you read, it allows you to click any word and receive an inline dictionary definition, and you'll mark each word on a 1-5 scale of familiarity, in order that you know how hard you should try and remember, until you eventually mark the word as known - and that can be quite the dopamine kick. This system is less efficacious for agglutinative languages, since you can only mark whole words. You may not try to remember a word recognized by the system as new, when in fact you may be familiar with its constituent elements. This, along with some other caveats of the language, is why Japanese is a whole different monstah.
SRS is a classic method for language learning. But if you want to become fluent, contant exposure to the language in its natural state is necessary.
As for some miscellaneous software, you might found this 3-part series helpful: How to Use Linux For Language Learning
日本語
/djt/
refold.la
The tl;dr for most guides: learn kana, then learn kanji+basic vocab with Anki as you watch/listen to anime all day - no English subs. Study some grammar sometime in there as well, but not too much, for the immersion will allow your deep learning algorithms pick up on a lot of it.
Refold Google Doc
Google docs sucks balls... one of the most powerful tech conglomerates the world has ever known and you can't even press Ctrl+F. Has everything you need outside of software, probably.
Learn Japanese with Anime
Just a list of anime sorted by their linguistic difficulty.
mpv-scripts
github.com/Ajatt-Tools
Memento
FOSS video player which I think has everything you need? without any work.
Here are some sites from tripfags on /djt/ with their owns guides and stuff.
tatsumoto-ren.github.io
animecards.site
DJT's Anacreon
Had a fucking hillarious video series on drama about Matt vs. Japan (founder of Refold) who fancies himself a bit of a businessman and an influencer. He isn't special. That being said, Refold is just another one of these congregations of info centered around the underappreciated Truth that is immersion-based learning, so I would encourage you to boycott him and just check out the guides and leave it at that.
Ancient Languages
You can't immerse yourself in a language that's dead, now can you? Well, for Latin, there's probably actually a decent ammount of audio out there considering it's somewhat popular, and it has Lingua Latina per se Illustrata, which follows a natural, immersion-like approach to learning.
But if the language you want to learn is really dead, then you're probably not aversive to doing it the old fashioned way anyways, and that's just the "grammar-translation" method. There's not exactly much of a purpose in training yourself to speak a language with no native speakers, or be "fluent" in it, per se. Work through textbooks, learning grammar and understanding more and more sentences, until you can read what you want. The question is what's the best material?
Lexicity
Early Indo-European Online
Ancient Greek
The 3 most distinguished dialects would probably be: Homeric, Attic (Plato, Aristotle) and Koine (Septuagint), but there's also Ionic, Doric, and a few others. But if there's one dialect to own the title "Ancient Greek", it'd be Attic - most textbooks are about it, and it has enough similarities with the other dialects and with modern Greek, such that jumping from one to another wouldn't be too difficult or anything.
Lingua Gracae per se Illustrata is a WIP project that replicates LLPSI.
Athenaze
Hansen & Quinn, Greek: An Intensive Course
Answer key, notes
If you know Latin, maybe you could also get by with reading some material right off the bat, say in a biglotic text, since something like 10% of Latin words are of Greek origin, they have similar morphologies, and similar grammars. See Sihler, Andrew L. New Comparative Grammar of Greek and Latin or something like that.
Pāli
Namo tassa bhagavato arahato sammāsambuddhassa.
It's probably a good idea to learn Sanskrit first, which is a treasure anyways, and is very standardized: the Aṣṭādhyāyī being a spectacle of scholarly rigour, to a degree that took contemporary linguistics took a long time to even approach. But modern grammars have had the opportuntiy to be written since 400 BCE.
