This is the 218th most frequent Swedish word.
snabbt
Quickly.
Here, 'snabbt' functions as an adverb, modifying the verb 'sprang' (ran) to describe the manner or speed of the action.
Hon sprang snabbt till bussen.
She ran quickly to the bus.
In this instance, 'snabbt' again acts as an adverb, illustrating the speed at which the subject acquired the skill.
Han lärde sig snabbt att tala svenska.
He quickly learned how to speak Swedish.
In this case, 'snabbt' is an adjective in its neuter form, describing the noun 'internet' (internet) to indicate its quality of speed.