First things first, I saw this announcement from Rick Brannan on Twitter earlier today:
This download was timely, since it helped me with this study. You can’t beat free!
Now, to the topic I wanted to discuss. In Acts 1:4 the NA 28 has a note at the end of the verse between ἠκούσατέ/ēkousate and μου/mou which states that in Codex Bezae (D, 5th century CE) and in the Clementine Vulgate (1592) there is an alternate reading (that was corrected in D). It is ην ηκουσα φησιν δια του στοματος μου/ēn ēkousa phēsin dia tou stomatos mou in Greek and quam audistis de ore meo in Latin (Codex Bezae has Greek on the recto and Latin on the verso). I found this alternate reading interesting not because there is any likelihood that it is original, but because I thought that it may provide interesting commentary on the text.
The Greek text should be translated “which you heard he said through my mouth”. Apparently, a later scribe corrected ηκουσα/ēkousa to ηκουσατε/ēkousate recognizing it as a misspelling (probably) and then corrected the additional phrase not found in other manuscripts. (The Latin text is similar being translated “which you (pl.) heard from my mouth”.*) Why did an earlier scribe write “the promise of the Father, which you heard (he said) through my mouth”?
Bruce Metzger had the following to say:
“The phrase φησὶν διὰ τοῦ στόματός μου of D it vg eth Hilary Augustine, which replaces the simple μου of all the other witnesses, is, as Ropes points out, probably ‘an expansion, ameliorating the transition to direct discourse and avoiding the awkward μου.’ (For a similar example of the vivid and homely style of the Western paraphrast, see the final comment on Mt 6.8.)” 
When I read the note in the NA 28 I thought that the scribe wanted to differentiate the discourse of vv. 4-8 from the statement in v. 2 that Jesus had “by the Holy Spirit given orders to the apostles whom He had chosen” (NASB; Gk. ἐντειλάμενος τοῖς ἀποστόλοις διὰ πνεύματος ἁγίου οὓς ἐξελέξατο ἀνελήμφθη/enteilamenos tois apostolois dia pneumatos hagiou hous exelexato anelēmphthē). In order to emphasizes that this discourse was being given by the resurrected Jesus who was physically present before his disciples before his ascension the scribe chose to emphasize speech by Jesus’ mouth. That said, I’m not sure what to do with ηκουσα/ēkousa. Is this an accidental misspelling or an attempt at another form? If another form is it 1s, aorist, active, indicative? How does that jive with the present, active, indicative of φησιν/phēsin?
There is another variation in this v. that may support my hypothesis. In 1:4a the text reads, “and gathering together with him” (Gk. και συναλισκομενος μετ αυτων/kai synaliskomenos met autōn). It would appear that συναλισκομενος/synaliskomenos is simply a misspelling of συναλιζόμενος/synalizomenos. More importantly, “with him” (μετ αυτων/met autōn) is not original. Is the scribe emphasizing that unlike v. 2 the disciples are now with Jesus in v. 4?
I’d like to hear your thoughts. If I overlooked or misread something that you think might make better sense of the variants let me know in the comments.
* My Latin is elementary, but if I read this correctly it is de + the ablative which is either “down from” or “from”.
 Bruce Manning Metzger and United Bible Societies, A Textual Commentary on the Greek New Testament, Second Edition a Companion Volume to the United Bible Societies’ Greek New Testament (4th Rev. Ed.), 242 (London; New York: United Bible Societies, 1994) citing James Hardy Ropes, The Text of Acts, being vol. iii of The Beginnings of Christianity, ed. by K. Lake and F. J. Foakes Jackson (London, 1926), p. 2.