I kinda view Echo as "Soul Speak" since Echo was considered one of the Archaic Psycic powers derived from sorcery.

Echo as an ability (Which most of what the power is in literature, myth, and general fiction was carried over just with it's own name) allows the user's soul to comunicate with the souls of others. If two people with the Echo were using it at the same time then it would be impossible to keep secrets from each other. Thus how the echo is not limited to "Language Barriers" since it's translating the soul's intent and emotions into words via what can basically be explained as telepathy.

So yea Echo= Soul Speak which allows you to "Hear" the soul of the other person thus the ultimate Deus Ex Machina power for rendering Language Barriers irrelevent in fiction.