If you’ve ever heard a sermon on the nature of the Holy Spirit, the speaker may have used John 14:16 as a reference:
“And I will ask the Father, and he will give another comforter to you, one that will be with you always.”
The Greek behind the English word, “another” is the adjective ἄλλος. It’s common to hear that there are two words for “another” in Greek: ἄλλος and ἕτερος. I can’t think of any English derivatives of ἄλλος, but ἕτερος is where we get our “hetero” words, like heterogenous. At any rate, ἄλλος (which is used here), means “another of the same type” in classical Greek, while ἕτερος means “another of a different type.” This distinction is still felt in the New Testament period, though the two words start to overlap more and more.
As always, with points of Greek usuage like this, I like to refer to the Greek fathers when possible. Their Greek is better than mine will ever be! Gregory, in his Oration on Pentecost (Or. 41), supports the distinction between the two words, and puts it to good use when discussing the Holy Spirit:
Διὰ τοῦτο μετὰ Χριστὸν μέν, ἵνα Παράκλητος ὑμῖν μὴ λείπῃ· «Ἄλλος» δὲ, ἵνα σὺ τὴν ἰσοτιμίαν ἐνθυμηθῇς. τὸ γὰρ «ἄλλος» οὐκ ἐπὶ τῶν ἀλλοτρίων, ἀλλ᾽ ἐπὶ τῶν ὁμοουσίων οἶδα λεγόμενον.
Because of this, after Christ (the Spirit came), so that you would not lack a helper. This helper is “another” (ἄλλος) so that you may know that he is one of equal honor. For the word “ἄλλος” does not refer to things of a different type, but we know that it said about things that are of the same nature (gk. ὁμοούσιος, the word used in the Nicene Creed to refer to the “consubstantiality” of the Godhead).
Scholars of Greek often lament the poor use of Greek in sermons, but this particular point is well-founded in our knowledge of Greek, and has precedent in the Church Fathers. One could, I suppose, argue against it, but it’s always nice to have Gregory of Nazianzus on your side.