Spanish is what the office reads
Files used in the Dominican Republic are read in Spanish, so a certified translation into Spanish in Newcastle upon Tyne is what turns an English record into something a Dominican office can act on. The whole sheet is carried over, not the interesting half: the header, the entry number, the district, the registrar's line and the wording inside every stamp. Anything left blank reads as information you did not supply.
Two surnames, one person
Dominican paperwork leans on family names far more than English paperwork does, and a birth entry there will usually name both parents in full. Your English certificate may show less. So check now that the parent names on your papers agree with each other, because a middle name present on one sheet and absent on another is the sort of thing that stops a file for a fortnight. The Spanish follows the English exactly, letter for letter.
The certification that is accepted
No court oath sits behind this route. What the Dominican Republic takes is a certified translation backed by a signed certificate of accuracy from a certified translator, naming the person who did the work and dating it. It is a lighter step than a sworn appointment and it lands the same way at the desk, because a named signer stands behind every line on the page. Keep it fastened to the Spanish text.
What it costs and how fast it moves
The figure is £25 for each page as issued, so counting the sides of paper in front of you gives the cost before anything starts. A folded certificate printed both ways is two pages. From a clean scan, standard work runs 2–3 business days, and express finishes in 24 hours. What slows a job is rarely the language; it is a photo taken at an angle in poor light, where half the registrar's handwriting has to be worked out twice.
Your own paper stays put
Only the translation is certified. The record itself keeps its own form and stays in your hands throughout, because everything is produced from the scan you send. Where the sheet you hold is worn or has been amended, Newcastle Register Office issues a fresh copy of a civil record, and starting from that clean version removes a round of queries. The office works by post, so allow a few days for one to reach you.