how many signs until I can speak/read somewhat fluently

[mint lichen]

what is your experience?

[hot lark]

What do you mean by signs?

[polar wasp]

characters

like how many characters (or words) you have to know until you can atleast understand and speak in a basic conversation

[tall ermine]

2k is the minimum to count as officially literate in China for a city dweller (1.5k if you live in the countryside), and should allow you to do basic reading. 2~3k would be like high school educated-level

speaking is not really related to how many characters you know, since it's a separate skill