For the Schengen vise do we need to translate the Thai marange certificate into English?

You will need to show evidence of a legal marriage, in order to verify that you are indeed married the embassy will need to see an official translation of the maritial papers in a language that they understand. Generally that means an English translation. 

 

Just to be sure:

I assume you are aware that a UK (or other EU/EEA national) visiting an other memberstate of the EU/EEA with their non-EU family member (spouse, durable partner, kids etc) will get their visa for free, via an expedited procedure that only requires making the family relation evident, ID of all those concerned and something that makes clear that the non EU traveller will join up with the EU national on the trip. See the Schengen sticky for details.