/!\ Word of Caution /!\

Demographic data being, obviously, absent for the period most of what is represented there is hypothetic either in placements, categorization or importance : as such the gradient represents possible dynamics at work, with languages growth or decline as well as bilinguism or sociolects.

Contextual knowledge is then highly recommended : for instance, Gothic in Spain was at this point a sociolect, part of the social codes of an heavily romanized group identifying itself as 'Gothic' whereas Late Gaulish in Central Gaul is a pre-Roman language dying out and spoken by rustic and remote populations otherwise not that socially different from their neighbours.

Accuracy of situation itselfs varies a lot depending of the avaible sources on toponimy, onomastics and contemporary texts : while in no way factual, situations in Gaul, Spain or Italy are still less theoritical and guesstimates than for transalpine regions or Central Europe.

Eventually, there was probably much more surviving pre-Roman languages out there than depicted (I personally tend to agree Hispano-Celtic could have well survived in the northern highlands during the Early Middle Ages) but it remains speculative and virtually unmappable in the current state of knowledge.

(It would, furthermore, likely be edited and corrected)

Based on this map of the Roman Empire by Andrei Nacu.