His extemporaneous speeches are marked by an enviable fluency.
Advanced English Dictionary
+noun [U, sing.] the quality of being able to speak or write a language, especially a foreign language, easily and well: Fluency in French and Spanish is required for this job. + to achieve / acquire / develop greater fluency + to build up a fluency in written and spoken English
Collocation Dictionary noun
VERB + FLUENCY
Some young children achieve great fluency in their reading.
Fluency in spoken English is essential.
Random quote: Everyone can taste success when the going is easy, but few know how to taste victory when times get tough.: Byron Pulsifer