The areas with more concentrated people and cities important enough to sustain strong states and commerce are the British Isles, the Alps and valleys an plains around them, some specific pockets in Gallia, Italy and the Iberian peninsula, southern Scandinavia and certain provinces of the Roman Empire.
The Romance speaking areas cover the Iberian peninsula, Gallia, Belgica, Italy, the western Mediterranean islands, NE Africa Proconsularis (modern Tunisia) and northern Transylvania. The area is sparsely populated, with denser pockets were petty kingdoms are centered.
The Basques are independent and have their own federation. No need to say they speak Basque.
The Celtic world (Ireland, Scotland, Northumbria, Wales, Cornwall, Brittany and western Normandy) recovered from the 525 Plague and is a thriving area devoted to fishing, farm and commerce. There are native speakers of Celtic languages in some areas of Iberia and Gallia.
The Roman Crown is the successor of the Roman Empire, it's centered on Basel, which is also the center of the Christian world, and covers an area that is, more or less, Germany, Bohemia, Austria, Switzerland (except Romandia), Lombardy, Veneto and Slovenia.
The Roman Empire is centered at Byzantium and covers the eastern Mediterranean. It's the largest state in the zone, but corruption, throne disputes and low population density in some crucial provinces makes it a weak giant.
There was no expansion of the Arab world thorugh northern Africa and the Iberian peninsula, so the Roman and Germanic peoples living there evolved quite undisturbed. In northern Africa the Vandal Kingdom thrives after the Great Plague and its a regional power, while In the Iberian peninsula various kingdoms and counties have developed: the Gallecian Kingdom in the NW, expanding towards the south along the Atlantic coast; the Asturian Kingdom, east of Gallecia, expanding southwards to the detriment of the Visigothic Kingdom, which covers much of southern Iberia, from Algarve to the Ebre. North of the lower Ebre we find some principalities and counties reunited into a confederacy centered at Tolosa; it's the Occitano-Romance cultural sphere, known as the Pyrenean Principalities from a political point of view.
Northern Africa is sparsely populated, with people concentrated in pockets along the coast north of the Atlasn mountains and the Nile valley. The two most important states are the Vandalic Kingdom, in the former Africa Proconsularis province (northern Tunisia) and the Crown of Egypt, a loose confederacy of princes, of Coptic culture.
Egypt is mostly a Coptic speaking country, with important pockets of Jew citizens. The Coptic religion, which is Christian, has its own church, being independent from Basel and Byzantium. The country is a confederacy of de facto sovereign princes, although they're nominally part of the Roman Empire and still faithful to it.
Berbers occupy most of the Sahara. Despite being nomadic they control a few coastal cities, most notably Tlemcen, Tripoli and Cyrene. They also control the transaharian trade routes.
The Vandal Kingdom is the most important state in northwestern Africa. Its inhabitants are a mix of Berber communities, descendants of Vandal migrants and descendants of the native Latin-speaking population. The most important language is a Latin tongue with a Germanic and Berber influence. Unlike our world the kingdom was never defeated by the Byzantine Empire, but it was affected by the Great Plague of 525.
The Great Plague of year 525 arrived from central Asia through the steppes, devastating much of continental Europe, with a special incidence in the Mediterranean coast and the Northern European Plain. Western Asia remained generally untouched, although the effects of the plague were notably suffered in the Levant and the Euxine Pontus.
The Persian Kingdom is recovering better than the Roman Empire and poses a threat to its western neighbour. The year of the Discovery king Khosrau V is expanding the kingdom towards the east and northeast, reaching Baluchistan (east) and river Oxus (north).
Islam has expanded throughout the Arabian peninsula, but not very far from this area. Its northenmost city is Palmyra, near the border of the Roman Empire and the Persian Kingdom.