Asante sana.
Just for your info, I have received via a Swahili site the one as yours and also the following:
Anaongea kifaransa kwa ufasaha.
Anaongea Yuruba kwa wepesi.
Anaongea kiswahili bila shida/bila matatizo.
I think that 'Anaongea kifaransa kwa ufasaha' is literally the best one, but I am still not sure which one is commonly used.
As
'sanifu' is 'standard'. eg. Kiwahili sanifu as opposed to its numerous variations spoken by indyviduals, NB Kiswahili has been granted recently an official lanuage in Kenya, but according to Kenyan newspapers, the problem is that even many PMs speak 'their own kiswahili' bit different to the 'sanifu'
'wepesi' = quickness, lightness (in weight) haste, ease
while
'ufasaha' = facility, clarity (of pronounciation) , purity of style, eloquence, elegance (esp. in speaking and writing