"Ya lo sé" or "Lo sé?"
SpanishDict translates both "ya lo se" and "lo se" to "I know", so does one need to use the "ya"?
4 Answers
"Ya" is a really interesting adverb (well, usually an adverb) because it means a lot of things depending on context. In the present tense it means now or already, except in a negative construction when it means no longer:
Ya lo sé - I already know it. Ya estoy listo - Now I'm ready. Ya no trabajo allí - I no longer work there.
In the past though, it almost always means already: Ya lo hice, I already did it.
In the future, it means later: Ya lo haré - I'll do it later. Or to offer assurance: Ya verás que llegará en punto - You'll see that he'll arrive on time.
It can mean since/because: Ya que no está aquí, no pedemos empezar. - Since he isn't here, we can't start.
To indicate frustration: ¡Basta ya! - Enough already! ¡Ya era hora! - It's about time!
To express agreement: ¡Ya, ya! - Oh sure! Or ironic, mock agreement: Ya, y el papa es luterano. - Sure, and the Pope is Lutheran!
You can drop the ya and just make it "lo sé."
The ya means now or already.
I agree with Greg.
"Lo sé" = I know (about it).
"Ya lo sé" = I already know (about it).
I am not too sure but I think this may be a regional thing. I believe, althougth Heidi might correct me, where's that corner now?, but they use the ya in northern and central Spain.