Ben Witherington talks here about his discovery of many unpublished commentary manuscripts by J. B. Lightfoot that Witherington discovered at the Durham Cathedral library while on sabbatical at St John’s College, Durham University (where I work, as it happens). Some of this material is found in the notes of Witherinton & Still (eds.) Acts of the Apostles, a publication of Lightfoot’s Acts material.
I was intrigued to discover how extensive Lightfoot’s learning was. Witherington says in his talk that Lightfoot could use 17 languages. He mentions “mastery” of German, French, Spanish, Italian, Latin, Classical Greek, Koine Greek, Patristic Greek, and a “working knowledge” of Hebrew, Aramaic, Syriac, Armenian, Ethiopic and Coptic (Witherington & Still 27–28).
Apparently Lightfoot would write out a passage from a Greek or Latin author (in the original language), evident because he would make a note to himself to check his quotation from memory and, when he had checked it, place a checkmark beside it.
Interestingly, in a note, Witherington says he has only met one NT scholar “even close to Lightfoot in these skills,” Bruce Metzger, with whom Witherington took a Summer course at Princeton (p. 37).