Rule reminder
Emphasis scale (additive): anche (neutral addition) < persino/perfino (unexpected/remarkable) < addirittura (extreme beyond expectation). Negative scale: non...neanche/nemmeno/neppure (not even) < non...mica (not at all, corrective) < non...proprio (really not, total refusal).
The speaker wants MILD addition: 'My colleague ___ speaks Italian.'