The only way that you could plausibly have this happen (IMO), is a slow, long lasting process.
An example might be that when the Visigoths seek shelter, the Romans agree, but rather than the dishonesty of Lupicinus and Maximus, instead they are ferried to the Anatolian Coast to be settled as Peregrini on the agreement that all the men of fighting age are to stay behind and serve, to go back to Northern Anatolia when they've completed that service to become citizens.
This at least leaves a large population centre that was mostly Gothic - now we can't have the Visigothic leadership being a nuisance, but they can encourage and help organise the Gothic-Roman community, and prevent rebellions by them, instead helping them organise, trading and swapping land payments to continue a cohesive Gothic-Roman community that speaks Gothic.
If this works, it could in theory be repeated with the Ostrogoths (Which would speed up the process of Gothificiation). Whilst this community isn't going to outnumber the Anatolians who already live there, but it becomes a prominent local language.
Now, we're working the premise that this community maintains a strong militaristic culture that takes the Romanitas idea of the Citizen/Soldier/Farmer to a level above that of most Romans (as much an attempt to be welcomed, as to take the idea to preserve a unique identity). This can be levied to be seen as deeply loyal, which could lead to a Gothic Guard as an idea, which is great for preserving the language.
Over time, this community can grow, and other members marry into it, learn the language, and over the intermediary 1000+ years, if we presume the idea of Goths can survive in the same way as Armenians and Greeks, it has a shot at becoming the dominant language. Especially if its so tightly bound to the Roman military, it could be a contender to form a successor state in some ATL crisis.
Its a long game, but a possibility. The key is the acceptance of the Goths as Peregrins.
An example might be that when the Visigoths seek shelter, the Romans agree, but rather than the dishonesty of Lupicinus and Maximus, instead they are ferried to the Anatolian Coast to be settled as Peregrini on the agreement that all the men of fighting age are to stay behind and serve, to go back to Northern Anatolia when they've completed that service to become citizens.
This at least leaves a large population centre that was mostly Gothic - now we can't have the Visigothic leadership being a nuisance, but they can encourage and help organise the Gothic-Roman community, and prevent rebellions by them, instead helping them organise, trading and swapping land payments to continue a cohesive Gothic-Roman community that speaks Gothic.
If this works, it could in theory be repeated with the Ostrogoths (Which would speed up the process of Gothificiation). Whilst this community isn't going to outnumber the Anatolians who already live there, but it becomes a prominent local language.
Now, we're working the premise that this community maintains a strong militaristic culture that takes the Romanitas idea of the Citizen/Soldier/Farmer to a level above that of most Romans (as much an attempt to be welcomed, as to take the idea to preserve a unique identity). This can be levied to be seen as deeply loyal, which could lead to a Gothic Guard as an idea, which is great for preserving the language.
Over time, this community can grow, and other members marry into it, learn the language, and over the intermediary 1000+ years, if we presume the idea of Goths can survive in the same way as Armenians and Greeks, it has a shot at becoming the dominant language. Especially if its so tightly bound to the Roman military, it could be a contender to form a successor state in some ATL crisis.
Its a long game, but a possibility. The key is the acceptance of the Goths as Peregrins.