It is funny once you get near level 10, Duolingo teaches you things to say when you are irritated.
I don't know why, but "eu sei como ler" sounds REALLY strange, not as much as "eu sei como nadar". It's probably not grammatically wrong, but as a native speaker I can tell you I never heard this sentence.
Useful to know. It does seem that with some verbs the "how to" idea is firmly built into the verb "saber" and Paulenrique mentioned in the other discussion that "saber como" was less common, obviously a lot less common.
He also said that "Você sabe como chegar ... ?" sounded natural, though, and I can see that in this case the idea of knowing "how to arrive" and knowing "how to" get to a given place are two different things.
The question "Você sabe como chegar a ... ?" gives the idea of asking directions to somewhere, you're asking the step-by-step of how to get to the place.
When you ask about someone's abilities, you'll probably just want to ask "Você sabe (ler/falar/nadar)?", similar to the meaning of "Are you able to (read/talk/swim)?"
More frequently, people use "saber como" when the next verb is in passive voice, to emphasize the way something is done: "Você sabe como se faz um bolo?" (Do you know how to make a cake?).
Can I say something like "Você sabe como ler textos arábicos? Da direita à esquerda!" ?
Yes, it would just sound more natural if you said "Você sabe como se lê textos arábicos? Da direita à esquerda!" because in that case you'll be asking if the person know how it's done (right-to-left), but not necessarily if they are able to read Arabic.
No, the only language I speak is British English, although after a long spell of studying Brazilian Portuguese I enjoy passing on what little I know, or more often, as in this case, what other people know.
Oh wow, well thank you for the little you do know! I've seen your comments on other threads and they help a lot!