is this translation correct?

τὴν μὲν άπαρίθμησιν λέγων ὅτι δεῖ πρότερον ὁρίσασθαι τί ὄνομα καὶ τί ῥῆμα, εἶτα τί ἐστιν ἀπόφασις καὶ κατάφασις καὶ ἀπόφανσις καὶ λόγος. In the recapitulation he says that it is necessary first to define what the noun is, and what the verb, then, what negation, affirmation, proposition and sentence are. Is it common for late Greek texts (this one is around 600 AD) to let active participles stand like that in independent sentences without any verb? Also, I find the Acc of τὴν μὲν άπαρίθμησιν somewhat unusual, it is not the direct object of λέγων but something else.

When it comes to the participle, I think it’s just strange punctuation, since it seems this fits well with the verb “διέξεισιν” coming just before: “ἐν δὲ τῷ β μέρει ἀναλογίαν τινὰ τῶν φωνῶν πρὸς τὰ νοήματα διέξεισιν. τὴν μὲν ἀπαρίθμησιν λέγων ὅτι …”

by the way, this διέξεισιν also gives trouble, should it be rendered as ‘he draws an analogy’ or ’ he expounds an analogy’?

I’m not sure “analogy” is the best translation of “ἀναλογία” here, since I think the sense is closer to “relation” or “correspondance”. So perhaps something like “… he recounts a relation between utterances and thoughts, saying that …”.

Constantinus,
You started your quote with a participle, not realizing that it’s not an independent sentence but just a continuation of the main sentence, which has the main verb (διεξεισιν).
And τὴν μὲν ἀπαρίθμησιν λέγων is a fairly common use of the accusative with λεγω, anticipating the ὅτι clause.

If you must translate, you could say “…, saying in summation that one should first define what a noun is and what a verb, then what negation and affirmation are, and ἀπόφανσις και λογος.” (Not “the noun” and “the verb,” and the concluding pair of terms are here used as specialized technical terms perhaps best left untranslated out of context.)

I like polemistes’ “correspondence” for αναλογια. “In Part II he details a sort of correspondence of sounds vis-a-vis thoughts.”

https://babel.hathitrust.org/cgi/pt?id=uc1.31822025606708&view=1up&seq=17

ΣΧΟΛΙΑ ΣΥΝ ΘΕΩΙ ΑΠΟ ΦΩΝΗΣ ΣΤΕΦΑΝΟΥ ΦΙΛΟΣΟΦΟΥ ΕΙΣ ΤΟ ΠΕΡΙ ΕΡΜΗΝΕΙΑΣ ΑΡΙΣΤΟΤΕΛΟΥΣ

<Ἀρχὴ τοῦ α τμήματος. Πρᾶξις α>

pg. 16a1 Πρῶτον δεῖ θέσθαι τί ὄνομα καὶ τί ῥῆμα. ἔπειτα τί ἐστιν ἀπόφασις καὶ κατάφασις καὶ ἀπόφανσις καὶ λόγος καὶ τὰ ἑξῆς.

Προοίμιον ἔχει ἡ παροῦσα πραγματεία διμερές. καὶ ἐν μὲν τῷ α μέρει ποιεῖται τὴν ἀπαρίθμησιν αὐτῶν τούτων περὶ ὧν μέλλει διαλέγεσθαι ἐν τῷ α τμήματι, ἔτι δὲ καὶ θεώρημά τι παραδίδωσιν· ἐν δὲ τῷ β μέρει ἀναλογίαν τινὰ τῶν φωνῶν πρὸς τὰ νοήματα διέξεισιν. τὴν μὲν ἀπαρίθμησιν λέγων ὅτι δεῖ πρότερον ὁρίσασθαι τί ὄνομα καὶ τί ῥῆμα, εἶτα τί ἐστιν ἀπόφασις καὶ κατάφασις καὶ ἀπόφανσις καὶ λόγος. καὶ αὕτη μέν ἐστιν ἡ ἀπαρίθμησις· τὸ δὲ θεώρημα τοιοῦτόν ἐστιν, ὅτι δ ὄντων, γραμμάτων φωνῶν, νοημάτων πραγμάτων, δύο τούτων φύσει εἰσί, τὰ δὲ ἕτερα δύο θέσει…

If anything that λέγων depends on the ποιεῖται, and we sort of jump past the ἔτι δὲ… and ἐν δὲ… sections. The editor has put his period in the right place.

EDIT (adding a bit more):

So my understanding is that Stephanus conceives two parts to the προοίμοιν, α and β. Separately, there are two τμήματα, α τμῆμα and β τμῆμα. Then there is the ἀπαρίθμησις, which is the line of Aristotle that has been quoted (16a1 Πρῶτον…ἑξῆς). Having not read the Aristotle here, I’m a little shaky about the divisions that Stephanus has in mind with προοίμοιν and τμῆμα, but I think this is right. Flipping through the book, I see that he marks β τμῆμα explicitly in the middle of the document.

The “τὴν μὲν ἀπαρίθμησιν λέγων…” at question does not fit logically with the statement about what he is doing in the β part of the προοίμοιν, of course. You could add parentheses to set off ἔτι δὲ…διέξεισιν, but it’s not actually a parenthetical statement. It’s stream of consciousness Greek that an editor can’t exactly fix without major revision.

What is the μέν of τὴν μὲν ἀπαρίθμησιν λέγων aiming it? Logically, the “τὸ δὲ θεώρημα…” that follows, but the author can’t get there directly due to the grammatical muddle he has made. So after re-quoting the ἀπαρίθμησις, he starts the statement over again, this time using a finite verb: “καὶ αὕτη μέν ἐστιν ἡ ἀπαρίθμησις· τὸ δὲ θεώρημα…”. And we’re off to the races.

(I suppose διέξεισιν is present tense, after the παραδίδωσιν. It could theoretically be future? following the μέλλει διαλέγεσθαι? I don’t know enough about the usage of -εῖμι compounds.)