Old English
Early form of English; Anglo-Saxon
Would a Pict be confused by Old English?
Old English was spoken by the Anglo-Saxons, a Germanic tribe that inhabited England. The Picts were a Celtic-speaking people that lived in what is now Scotland. The Pictish language died out by 1100AD and was replaced by Gaelic. Gaelic and Old English are completely different languages from different branches of the Indo-European language family. Gaelic vocabulary is very different from Old English  and verbs are also conjugated differently.
What language was spoken by the Picts? In what language family is Old English? Is #2 not closely related to #1?