For Latin you might like Lingua Latina per se illustrata. It teaches Latin solely through Latin itself, starting with simple sentences. As such, it's mostly focused on reading Latin. You can also look for the "Nature Method" books available in Italian and French (and there's supposedly a Russian one, but I haven't found a scan of it and only know of one copy hidden away in a university library in the US). It's my goal to be able to update these one day, but I believe they're still under copyright except in the US.
Lingua Latina seconded. It’s a tremendously powerful to acquire Latin on such an intuitive level that you will find yourself thinking in Latin after a while. A lot of fun!
