A Thai brand voice does not survive being written in English first
The politeness system that carries most of the meaning in Thai has no equivalent in an English brand guideline, so it gets decided by whoever translates.
A brand voice document arrives specifying warm, confident, approachable, with three do-nots and a tone slider. Rendered into Thai, the most consequential decision in the whole exercise — the level of formality and the particles that carry it — is made by a translator working alone, because the guideline does not contain the concept.
Formality is not a dial in Thai, it is a relationship
The choice encodes who the brand thinks it is relative to the reader: an elder, a peer, a service provider, a friend. Get it wrong towards formal and a youth brand sounds like a bank. Wrong towards casual and a financial brand sounds like it should not be trusted with money.
English has no equivalent lever, so the guideline is silent, so the decision is invisible, so it is never reviewed. It then differs between the website, the LINE account and the customer service replies, which is how a brand ends up sounding like three companies.
What a Thai voice guideline needs that an English one does not
- A stated register, with examples, for each surface — and a reason if they differ.
- Particles, decided rather than left to the writer. They carry politeness and warmth and they are not decoration.
- How the brand refers to itself and to the reader, which is a positioning decision in this language.
- Worked examples of the same message at the right register and one step wrong in each direction.
The English guideline says be friendly. In Thai, friendly is about six different decisions and one of them can lose you the account.
