[Kolokotronis]

“the Spartans communicated in the monosyllabic grunts of Doric Greek.”

We did not and certainly do not communicate in “monosyllabic grunts”. We do listen to and understand koine Greek in the reading of the Epistle and the Gospel every Sunday. The rest of the Divine Liturgy is chanted in Byzantine Greek, which is rather more complex. It never ceases to amaze me how the lousey translations of the NT and the Septuagint used in most of the Western world continue to lead to such miserable heresies.

[Verginius Rufus]

The Spartans weren't even in Alexander's army. During his campaigns in the East, the Spartans led by King Agis III were fighting his viceroy Antipater (unfortunately the Athenians held back and the Spartans were crushed). After his victory at the Granicus River, Alexander dedicated the spoils as "from Alexander and the Greeks, except the Lacedaemonians."

I think the years of Alexander's campaigns were too brief to have much impact on the language. Koine is close to the classical Attic dialect--I think the importance of Athens in the 5th and 4th centuries (as a cultural and economic center and as the political leader of the fifth-century Athenian Empire and the fourth-century Second Athenian Confederacy) had more to do with the emergence of the Koine dialect.