Hans Förster (University of Vienna) has published a fascinating article in ZNW on a supposedly incomplete sentence in John's gospel, demonstrating how a scholar can integrate philology and textual criticism in a number of useful ways (manuscripts, commentaries, versions and basic grammar all come into play). I am very grateful to the Austrian FWF for supporting this work and also for making the article freely available online! I have highlighted the key phrase below and also link to the German PDF.
Parts of John 8,25 – the words of Jesus – present serious problems for interpretation. They seem to be an incomplete sentence. Therefore, their meaning is elusive and it is uncertain how to translate them. These problems can be solved if close attention is paid to the evidence of Biblical manuscripts for this very passage. If these manuscripts are used for constructing the text, there is no incomplete sentence at all. John 8,25 becomes a crucial part of the discussion between Jesus and his Jewish opponents in chapter 8 of the Gospel of John.
Ἔλεγον οὖν αὐτῷ· σὺ τίς εἶ; εἶπεν αὐτοῖς ὁ Ἰησοῦς· τὴν ἀρχὴν ὅ τι καὶ λαλῶ ὑμῖν;