It is an inflection of the verb fablar ("to speak"), which is an archaism and today is written "spoke", the /f/ having been replaced by a /h/, and the /u/ again by a /v/ and finally by the /b/. It should be clarified that although this verb form has not been used for centuries, it still appears in the dictionary of the RAE (twenty-third edition), of course in the infinitive; Because as anyone who has ever used a dictionary knows, definitions are only in infinitive and other impersonal forms. The conjugation of such ancient versions are only available in specialized publications for philologists, historians, literati, and researchers in general. See verbs/spoke.
