They would be the same, but 'linguistical' is very rare, though we do use 'linguistically'. Often -al signifies an adjective and its absence a noun, e.g. 'mathrmatical' and 'mathematics', but 'botanical' is a noun, while both 'botanical' and 'botanic' work as an adjective; you just have to remember each one individually. -al is a bit more favoured here in the UK than in the US, you wouldn't find us writing 'geographic' or 'geologic'.