تبیان، دستیار زندگی

supposing a person who is speaking fast carelessly! I think s/he should speak much slower in order not to make many mistakes! keeping on making many mistakes are annoying...

on the other hand, there are people who speak fluently and makes some mistakes that we can ignore them! So, I think here the benefits of fluency outweigh the accuracy
doesn"t it?!  

so, making mistakes because of speaking fast
or because of not having the required knowledge ?

To answer your question, I"d like to mention that I meant accuracy is really necessary to avoid annoying people who are listening to us
If the mistakes are ignorable, it would be OK to speak fluently ...I can"t think of anything else right now. 

Good judgment comes from experience, and often experience comes from bad judgment. ~Rita Mae Brown

corresponding to this we can say

fluency comes from experience, and often experience comes from inaccuracy

what do you think?

I got your idea,

we should make a balance between speaking fast and speaking accurately

so, making mistakes because of speaking fast"
or because of not having the required knowledge ? "

I meant making mistakes not errors! in the other words, mistakes that you would not made if you spoke slower.!

"fluency comes from experience, and often experience comes from inaccuracy"

eh...let me think more please!

aha! yes, I think I could manage to get your idea! it"s a kind of philosophical sentence! did you make it on your own spontaneously?

yeah,
you are right

great point
the difference between error an mistake

I would say it is practice that makes perfect