The readings were already in the vernacular in almost all jurisdictions well before VII. The norm was to read them in Latin first and then repeat them in the vernacular. However, the three-year cycle was a major change as was the addition of a second reading before the Gospel.
To be precise, the Mass had already been translated into dozens of languages before Vatical II. I personally own Missals with French and English translations that pre-date the council by at least a decade. The change was that the translations could get the official endorsement of the Vatican and could be used, under some conditions, by both the celebrant and the congregation during Mass.