It 'talks' in whatever language the station it is broadcasting uses, if a French station French if its Swahili then the same, there's no such thing as a multi lingual radio, surely you can fit/upgrade to any radio and speaker system that has same physical dimensions with no need for enlarging the cut outs, if you choose either radio or speakers that are bigger then you are going to start cutting the holes where they are fitted to get them in, is cutting going to have any bearing on the vans warranty, as for DAB I wonder if the existing antenna would support the digital signal but I would expect any half decent car radio forum which I'd expect to be easy to locate to advise on this,
BP