While I was pretty good with Greek while in seminary, I've lost a lot of it over the years. Since there are many here who haven't, I thought I'd throw this question out.
Ἅγιος ὁ Θεός, Ἅγιος Ἰσχυρός, Ἅγιος Ἀθάνατος, ἐλέησον ἡμᾶς.
This is the EO version of the Trisagion; the OO version includes a Christological phrase before ἐλέησον ἡμᾶς to make clear that we address it to Christ and not to the Trinity, as the EO do.
Grammatically, is this addressed to one person or to more than one? The Copts just adopted the Greek for this, and yet they address it to one person. My understanding of the grammar is that it's directed to one person and not to three. I'm interested in the grammar; theology and polemics can be done elsewhere (and if they have already been done, just let me know, and I'll look for that). Are the Copts "doing it wrong" grammatically, or does the Trinitarian interpretation of the EO come from somewhere other than grammar?