"Müller" in Germany = "Muller" in domains. .de supports ü, .com doesn't. Register both müller.de AND muller.com or lose traffic. Diacritics = double registration cost.
Domain Limitations
Internationalized Domain Names (IDN) exist but poorly supported. Email clients block IDN addresses (phishing risk). Users type ASCII versions. "café.com" becomes "cafe.com" automatically.
Search Behaviour
Germans search "Müller" with umlaut. Google returns "Muller" results too. But "Müller" ≠ "Mueller" legally. Trademark covers one, not both. Need separate registrations.
The Triple Cost
Brand "Größe" requires: (1) "Größe" trademark with ß. (2) "Groesse" trademark (German ß → ss convention). (3) "Grosse" trademark (international simplified). Triple filing fees.
Logo Solution
Register stylised logo trademark with diacritics. Logo = distinctive, not dependent on character accuracy. "Nestlé" logo protects regardless of accent rendering.
The French è Problem
"Première" in France = "Premiere" elsewhere. English keyboards lack è. Customers type "Premiere" automatically. Register both or competitor squats ASCII version.
German ß Evolution
Traditional: ß in lowercase, SS in uppercase. 2017: Capital ẞ introduced. Inconsistent adoption. Older systems don't recognise ẞ. "STRASSE" vs "STRAẞE" = legal variants.
The Safe Route
Avoid diacritics entirely. "Cafe" not "Café." "Muller" not "Müller." ASCII-only = universal compatibility, single trademark, one domain. Simplicity = savings.
Trademark Lens checks both diacritic and ASCII variants automatically - reveals conflicts across spelling variations before registration.