Formal or informal? Choosing a tone of voice for Czech customers

It's the first question a brand entering the Czech market runs into, often before writing a single email: address customers informally (tykání — like French tu or German du), or formally (vykání — vous, Sie)? And it's a question with no universally correct answer — only an answer that's correct for your brand. What does exist is a decision framework, and one rule whose violation every customer notices instantly.

The same logic applies across most of Europe: German, French, Polish, Spanish, and Italian all draw the same formal/informal line. Czech just happens to enforce it with particular vigor.

What the market does

The overwhelming majority of Czech e-shops use formal address. Informal address is reserved for brands targeting younger audiences, sport, hobby, and lifestyle — wherever the brand should feel like a friend, not an institution. Formal is the safe choice for a broad public, premium categories, and anywhere multiple generations shop at once.

That doesn't mean formal is "correct." It means informal is a decision — and decisions have to be made consciously, not by having half your copy written by a copywriter who prefers ty and the other half by an agency that prefers vy.

The decision framework: four questions

1. Who is your customer? Not on paper — who actually orders. A skate shop with an average age of 24 goes informal naturally; a wine shop where thirty-somethings buy for their parents loses nothing with formal.
2. What's the brand's personality? A friend who recommends ("grab the wider fit") or an expert who advises ("we recommend the wider fit")? Informal address commits you to a whole informal register — you can't use ty and simultaneously write like an insurance company.
3. What does your category tolerate? Cosmetics, coffee, and outdoor gear can carry informality. Medical supplies, luxury watches, or anything where the customer is in a sensitive situation almost always want formal.
4. Can your whole team sustain it? The tone has to survive customer support on a Monday morning and a complaint-resolution email. If support naturally writes formally while the website is informal, the customer is talking to two different brands.

If you're unsure after all four questions: go formal. Formal address with a warm, human vocabulary ("we're happy to help" instead of "your request has been registered") reads friendly today and risks nothing.

The iron rule: one register, every surface

The formal/informal choice matters less than its consistency. And this is where most stores break — not on their own copy, but on third-party apps that speak on their behalf:

• the website and product copy is written by you,
• transactional emails are generated by the platform,
• the review widget ships its own translation,
• checkout speaks the payment provider's language,
• and the loyalty program — often machine-translated — uses formal address while you're informal. Or worse: mixes both in one sentence.

The customer doesn't distinguish who wrote which text. Everything is "the brand." One machine-translated widget shouting an awkwardly translated "Redeem your rewards now!" undoes a tone you spent years building.

An audit you can do in one afternoon

Walk the full purchase as a customer and list every surface with text on it: homepage, product page, cart, checkout, confirmation email, shipping email, review request, loyalty widget, chat, complaint form, invoice. For each, note: informal, formal, or mixed? The result is usually a surprise — and a ready-made brief at the same time.

For third-party apps there's a single criterion: they must give you full control of the copy. Not "we have Czech" — but the ability to rewrite every customer-facing string into your register. Charm is Czech-native rather than machine-translated, and you can tune the program's copy to your own voice — including how you address customers by name.

If you already have a register and want to switch

Moving from formal to informal (the more common direction) is a small rebrand: do it all at once, everywhere, knowing part of the audience won't love it. Pair it with a redesign or repositioning — half a year of mixed forms is worse than either form alone.

Formal versus informal is, in the end, a smaller decision than it looks. The consistency with which you hold it on every surface — including the ones you didn't write — is what the customer actually experiences as the brand.