Writing Ad Copy for Four Languages Without Losing the Offer

Translating ad copy word for word produces text that is grammatically correct and commercially flat. The offer survives the translation, but the reason to click does not. Producing copy for several markets at once is a writing process, not a translation process.
Write the argument first, in one language
Before writing anything in the target languages, write out the argument in the language the brief was given in: what problem the product solves, what proof exists, and what the reader is being asked to do. Keep it to four sentences. That is the payload every language version has to carry.
Rewrite, do not translate
Give a native writer the four-sentence argument, the character limits and the platform’s policy constraints, and ask for copy that would work if it were written from scratch. Word-for-word translation is only appropriate for regulated claims, where the exact wording carries legal weight.
Watch the length physics
The same idea takes noticeably more characters in some languages than in others. Titles that fit comfortably in English may need to be shortened before they are written, not after. Deciding which element of the argument to drop per language is easier when the writer knows the limit up front.
Keep a shared glossary
Maintain one glossary per market covering product names, feature terminology and prohibited claims. It prevents three writers producing three different names for the same feature, which is the most common reason a multi-market account looks inconsistent six months in.
Read it aloud in the target language
Copy that is awkward to say is usually awkward to read. A short read-aloud pass catches phrasing that a spell checker will never flag.