I am learning Latin from Duolingo and when i finish Duolingo, i am planning to move to Lingua Latina Per Se Illustrata, the famous book.
In this context i am wondering that when i finish these two, would i have enough Latin to understand Sextus Empiricus' famous Adversus Mathematicos ( Against those in the disciplines )?
Here you can find the Latin text to check.
Congratulations on setting for yourself a worthy goal!
I think that Duolingo and Lingua Latina are great places to start. Once you graduate from them let me recommend that you dive straight away into your enthusiasm, Sextus Empiricus. I predict, however, (as cmw said in a comment), that you will still find it a very tough slog. So for help let me recommend a few extra resources.
I think that then you will find that you could benefit from a more formal grammar than Lingua Latina provides. You have a huge variety of sources. Lots of folk here on Stack Exchange quote Allen and Greenough, which I think will do fine. Reginaldus Foster, the famous Latin teacher, recommended Gildersleeve and Lodge, 3rd edition, unabridged, which I heartily recommend. Both of these texts are available free as PDFs on the internet.
Manuel Cauã Rebouças mentioned in a comment a good dictionary. This is a must. If you know English well, Lewis and Short will probably serve you well. Perseus has a good gateway to it on the internet for free. If you want a paper copy, it is very heavy and pretty expensive. Mine set me back $220 twenty years ago, but I do not regret it one bit.
It is so heavy, however, that I also bought a small handbook dictionary. Lots of scholars recommend Cassell's, which I own, and it's fine, but I much prefer to use Traupman's for a variety of reasons. These are good for keeping in your backpack or on your end table, and I own several of these. But for really hard words, you'll still need the monster, Lewis and Short.
But what you will really need is perseverance. This will be tough. If you love your text enough, you will keep with it. If you tire of your text, you might want a brief diversion (Harrius Potter? Ille Hobbitus for me. You will find your own favorites.) to recharge the old enthusiasm before you dive back in.
My final recommendation is that you try the waves-up-the-beach method. Your first sentence will be your hardest sentence. Your first few paragraphs will be your hardest paragraphs. At some point, you will lose the thread, founder, and have to give up and go back to your text books. When that happens, start over at the beginning of Sextus and work yourself back up to (and hopefully past) your last breaking point.
And my final final recommendation is USE THIS SITE. It is a superb resource for helping you understand that really incomprehensible sentence or word which defeated your last attempt.
Best of luck!
