That's indeed an interesting entry, Aurelia.
The episode in itself seems to be exact but the quoted figures (eg, [sIC]"by 1180, it is estimated that up to 60,000 Latins lived in Constantinople") seem to me to be absurdly high; that would have been roughly like half the population of Venice, the entire Genoa or two times Paris by the late XII century.
The article quoted no primary sources; all in all, it seems suspiciously apologetic for the forthcoming IV Crusade.
In any case, I don't think this is what Ludovicus had in mind; these unfortunate Italians were "Latins" for their Christian rite; they surely spoke some contemporary romance language(s), not any real Latin.
Yes, I know Ludovicus meant something else. I was just going along with what Kosmo said above about merchants of Italian origin, crusaders, mercenaries and so on.