Herodot, definition of "barbarian language"

Herodot lib. I 57 and 58 , cf. ibidem I 178 -- so I found it
in Prehistoric Dacia of N. Densu$ianu, 1913

Translation is made by me, so please be carefully with it.
Better take a look in a authorised source or in your own
sources for this.The

"What a langauge used the pelasgians I cannot say very sure;
but if we are allowed to make a conclusion after the
pelasgians who still today live in the city of Crestonia below
of Tursens ( in the oriental part of Macedonia, near meer) and
who once inhabited the region called today Thessaliotis.. and
if we will keep in mind that the langauge of pelasgians who
builded the cities of Placia and Scylace from Hellespont and
who before lived together with Athenians, we would say, the
pelasgians used a barbarian langauge..."

From what Herodot say, we could just understand that this
"barbarian" language was not just everything which was not
greek, but a certainly language. But what about, we still know
nothing. This is why I asked in a precedent mail about a
selective definition of "barbarian langauge".