Cornelius Nepos, On the Roman Historians, Atticus, 4.1:
Huc ex Asia Sulla decedens cum venisset, quamdiu ibi fuit, secum habuit
Pomponium, captus adulescentis et humanitate et doctrina. Sic enim
Graece loquebatur, ut Athenis natus videretur; tanta autem suavitas erat
sermonis Latini, ut appareret in eo nativum quendam leporem esse, non
ascitum. Item poemata pronuntiabat et Graece et Latine sic, ut supra
nihil posset addi.
When Sulla arrived at Athens in his journey from Asia, he kept Pomponius
in his company as long as he remained there, being charmed with the
young man's politeness and knowledge; for he spoke Greek so well that he
might have been thought to have been born at Athens; while there was
such agreeableness in his Latin style, as to make it evident that the
graces of it were natural, not acquired. He also recited verses, both
in Greek and Latin, in so pleasing a manner that nothing could have
been added to its attractions.
[J. Watson's Loeb edn.]
Is this evidence that Greek at Athens during Sulla's time there (late 80s BCE) or at the time of Cornelius' writing (d. 25 BCE) was perceptibly different to Greek elsewhere, for example in Asia Minor ?