Knowledge of Tagalog regions and dialects is valuable in English to Tagalog translation. Tagalog translators in the Philippines will not be coming from one locality. When they speak, native Tagalog speakers will immediately give away their origins because of their different accents.
People in the Tagalog provinces will likely have a stock of words unknown to city residents. Among these words, expressions from the south are sometimes labelled "deep Tagalog". In fact, translation reviewers give this general comment every time they can't understand the translation. But what is difficult for Manilenos (NCR) may be everyday words for Batanguenos (South Luzon), and terms understood by folks in Bataan, Bulacan and Nueva Ecija (North Luzon) will probably be Greek to people in Quezon (South Luzon).
The translator's home base. A translator based in Nueva Ecija, Bulacan, Manila, Rizal, Laguna, Quezon, Cavite, Mindoro, or Palawan may refuse to compromise his or her "ear for Tagalog". Catering to a regional "ear-for-Tagalog" will affect diction or choice of words, grammar and syntax, and idiomatic expression.
Dialect preferences sometimes weaken a translation, and sometimes strengthen it. Knowledge of dialects offers an advantage specially when back translating or editing the text.
A grasp of Tagalog regions and dialects may also help in compiling objective editing and back translation standards towards choosing, evaluating, and producing either a formal equivalence or a dynamic equivalence.