ἔστι δέ, ὥσπερ ἐν τῇ ψυχῇAnd Ackrill's translation:
[16a.10]οὔτε ἀληθές πω. σημεῖον δ' ἐστὶ τοῦδε· καὶ γὰρ ὁ τραγέλα-
εἶναι ἢ μὴ εἶναι προστεθῇ ἢ ἁπλῶς ἢ κατὰ χρόνον.
Just as some thoughts in the soul are neither true nor false while some are necessarily one or the other, so also with spoken sounds. For falsity and truth have to do with combination and separation. Thus names and verbs by themselves--for instance 'man' or 'white' when nothing further is added--are like the thoughts that are without combination and separation; for so far they are neither true nor false. A sign of this is that even 'goat-stag' signifies something but not, as yet, anything true or false--unless 'is' or 'is not' is added (either simply or with reference to time).A quibble: I might have put "while some necessarily are one or the other", to avoid the (slight) suggestion that Aristotle has in mind modal truth, rather than bivalence.
That passage seems relevant because:
(i) it shows how Aristotle uses τὸ εἶναι ἢ μὴ εἶναι as a stand-in to signify the occurrence of "is" or "is not" in an assertion;(Curiously, in a blog infra is supra!)
(ii) it suggests that εἰ ἔστιν ἢ μή οὔπω σημαίνει (infra) is likely to mean "does not yet signify whether it is or is not truth"; and
(iii) it indicates that by προσσημαίνει δὲ σύνθεσίν τινα (infra) Aristotle likely means precisely that sort of combination that results in an assertion with a truth-value.