Of course. But if I worte a song and gave you a lead sheet, you wouldn't be able to play it, unless I played it to you, or I gave you a recording. If you can read music you wouldn't have to hear the song first. It's exactly the same as language. If you can't read, you have to rely on someone telling you. And do people always tell the truth? Not always I'm getting a bit off topic I know, but I can't stress enough about how important it is to be able to read music and be able to write. If you have a song and you want a string orchestra, a sax section, three trumpets and three trombones to play your song as well as the'band', it's far easier to arrange the song as a score for all instruments then make parts and distribute them to the musicians. They can then read them and play the song immediately. Otherwise you basically have to teach each part to each musician, a time consuming effort and one with potential mistakes. Ok, I'll stop my rant now. It's just very important to me and what I doquote:It all depends on how you define it I guess.
From a piece of notation I can tell what key a song is in and I know which notes are which but I can't sight-read nor have I been able to grasp converting the timing properly, preferring to rely on ear.
This is just my opinion, there is nothing directed personally at anyone one person on this forum Just in case